When I was seven, my family spent a week in Japan to promote the remake of Miracle On 34th Street. Within three days, I was ready to become an expatriate.

“This is so much better than the United States!” I told my mother as we walked back to the hotel with brand new kimonos. I bowed my head to the people we passed. A Japanese businessman smiled at me and bowed back.

“See?” I said. “Everyone likes us.”

They liked me, anyway. Our translator, Kuni, had told me as much. When Miracle was screened at Tokyo Stadium, I had gone out to introduce it. “Do you hear what they’re saying?” Kuni said after I walked off the field.

“Kawaii,” she said, smiling. “She’s so cute!”

It hadn’t occurred to me that I was cute. My family told me I was beautiful, but I had never been one of the prettier girls in my class. The pretty girls were a different breed. It was probably as much of a shock to them as it was to me when I was cast in a movie, but at that time, casting directors wanted kids who looked “normal”. As long as we could memorise our lines and say them with some feeling, no one cared how symmetrical our faces were. And it had worked: I had tricked entire countries into thinking I was cute.

John Hughes had been assigned to write the script of the Miracle remake, and the part of Susan, the young girl played by Natalie Wood in the original, had been rewritten as a boy named Jonathan. Christopher Columbus, who directed Mrs Doubtfire, my first film, must have put in a good word for me, because the script ended up in my mother’s hands. I liked Jonathan/Susan right away; she seemed smart. A few days later I read my lines for the production team and told them I didn’t believe in Santa Claus, but I did believe in the tooth fairy and had named mine after Sally Field. They laughed, thanked me for my audition, and within a few weeks had changed Jonathan back to Susan. I had the part.

With Richard Attenborough in 1994’s Miracle On 34th Street. Photograph: Rex/Shutterstock

My mother hadn’t pushed me into acting. We lived in Burbank, 20 minutes from Hollywood, and lots of people I knew were involved in the industry in one way or another – including my father, who worked as an electronics engineer at CBS and NBC, and my older brother Danny, who had been in a few commercials. I begged my mother to let me do the same, and before we knew it, I was cast in Mrs Doubtfire. My parents were proud, but they kept me grounded. If I ever said something like, “I’m the greatest!” my mother would remind me, “You’re just an actor. You’re just a kid.”

Both my mother and I liked John Hughes right away. He didn’t talk down to me, and he was from the same suburb of Chicago as my mother. But once we started filming, I could tell she had doubts about the remake. John didn’t have much say any more: once a film is in production, the script no longer belongs to the screenwriter. Script changes were mostly left to our director, who didn’t have much professional experience. My mother’s instinct was not to interfere, but it had always been hard for her to keep her opinions to herself.

Anytime someone said I was cute, I would wince. Something about it made me feel smaller

“Are you sure you want Mara to say ‘uncharacteristically’?” she asked him after a rewrite. “She’s still getting over her lisp.” Of course he wanted me to. It was adorable to make a six‑year‑old with a speech impediment say an eight‑syllable word.

As the months went on, my mother went from furtively asking, “Are you sure?” to demanding to know why a change was being made.

“Why is she wearing a hair ribbon to bed?” “Well, you know,” he would say. “It’s cute.”

I could sense her disappointment. They were making Susan as cute as possible, and taking away her intelligence and complexity.

All through the last few months of Miracle and our publicity tour, my mother smiled whenever people told her I was cute, but I could sense she was forcing it: she didn’t care for cuteness, and her disapproval was contagious. After that, anytime someone said it, I would wince. Something about it made me feel smaller.

With Robin Williams in Mrs Doubtfire in 1993. Photograph: Rex/Shutterstock

Apparently the film version of me was polarising. Some outlets loved me: Entertainment Tonight, the TV show, asked me back again and again. Others weren’t feeling it. One woman at a film magazine I’ll call Entertainment Twice-a‑Fortnight was particularly brutal, referring to me as “Mara Wilson, who lisped her way over‑fetchingly through Mrs Doubtfire and continues the tiresome act here.” She devoted an article to “the risks of being too cute as a child actor”, but rather than complain about directors and producers who treated children like dolls, she reserved her ire for me. When she saw me smile, all she wanted was – and these are her own words – “to shake her by her tiny adorable shoulders until her little Chiclet teeth rattle”. In some ways, it couldn’t be helped. It was still the early 90s. Grunge and nihilism were in. What better way to show one’s edge than hypothetical child abuse?

***

By the time I started filming Matilda the next year, I couldn’t wait to get older. When Kiami Davael, who played Matilda’s best friend, Lavender, turned nine while we were filming, she had been allowed to work for another hour a day. I couldn’t wait to work nine hours a day. But that wasn’t all: I wanted the freedom my teenage brothers had, to do all the cool things they did, like driving and going to concerts without a chaperone. Most of all I wanted people to stop thinking I was younger than I was.

Soon after Matilda wrapped, I lost my mother to cancer, 13 months after she was diagnosed. My father became so overprotective he wouldn’t even let me cross the street by myself.

For a few years after that, I ended up passing on most of the scripts that came my way. The characters were too young. At 11, I had a visceral reaction to a script titled Thomas And The Magic Railroad. Ugh, I thought. How cute.

With Danny DeVito and Rhea Perlman in Matilda. Photograph: Rex/Shutterstock

“You have to say yes to some projects if you want to keep acting,” my father said, but I shook my head. “Look,” he said, “if you do it, it’ll be a short shoot, it’ll be in the British Isles, it will be fun. The director’s supposed to be really nice.”

She was really nice. Britt Allcroft was a gentle, slightly eccentric, grandmotherly woman who was full of ideas, and after we met, I couldn’t say no to her.

We filmed for a month on the Isle of Man, and spent a month in Toronto doing interior scenes on a sound stage. My father had to work, so I went on my own. A week into filming in Toronto, Britt came into my trailer and sat down next to me on the couch, looking serious.

“Mara, when we first started filming, you were 11, still a little girl, but now you’re a grownup 12‑year‑old…”

I had an uneasy feeling, the same kind that comes from knowing an adult is about to talk to you about sex and there is no way to stop it from happening.

“And there’s a difference, a difference in your body. We’ve noticed it when we watch the dailies. So, maybe if you could wear a sports bra…”

After Britt left, Lucy, my set caretaker, laid out some white sports bras on the bed. My gaze met hers, and I knew she had noticed, too. They had all discussed this beforehand without my knowledge. Puberty had arrived, and I was the last to know. I looked down at the floor, tears stinging my eyes. “Oh, don’t look so sad,” Lucy said, giving my shoulder a squeeze. “It’s not a bad thing. Boobs are fab!” I had never felt so alienated from my own body. The change I was experiencing would have been uncomfortable enough in private, but I was going through it under public scrutiny.

With her parents at the Mrs Doubtfire premiere in Beverly Hills in 1993. Her mother died of cancer in 1996. Photograph: Getty Images

One day, age 12, I made the mistake of looking myself up on the internet. A website called Mr Cranky wrote that I was popping up in every movie these days because I would soon be entering “the awkward years, when she’ll be old enough to have breasts, but not old enough to show them legally”. I folded my arms over my chest just reading that, and even as an adult it makes me shudder. Who did they think they were, talking about a preteen girl’s breasts?

It got worse. The next page of search results linked to a website with a description that said, “If you want Mara Wilson nude and sex pictures, click here.” My stomach dropped and my heart pounded as I desperately tried to make sense of it. Maybe there was some kind of porn actress who had the same name. Or what if I had been drugged and kidnapped and then somehow made to forget the whole thing? Some rational part of my brain remembered that there was such a thing as photo manipulation, that they could put my head on someone else’s body. But that didn’t make me feel any better: who was this poor anonymous girl whose body stood in for mine? I burst into tears.

It was just the beginning. A few months later I found out I was listed on a foot fetish site that catalogued scenes in movies where children’s feet could be seen. Then there was the fan letter from an adult man who said he loved my legs and wanted my lip print on an index card. There was even a rumour on IMDb that I had died of a broken neck in Bridgeport, Connecticut.

At 13, no one had called me cute or mentioned the way I looked in years, at least not in a positive way. My sixth-grade crush had called me ugly, film reviewers said I was “odd looking”, and a boy at my preteen day camp had said to me, “You were Matilda? Heh. You’ve gained a little weight since then!” I went home and cried into a milkshake.

When I was alone, I could admit to myself that acting wasn’t as fun as it had once been. But I had to keep doing it, didn’t I? It was the constant in my life. My family had changed, my body had changed, my life had changed. Sometimes it felt like acting was all I had.

A few months later, my father asked after another script. “Catch That Kid?” I said, incredulous. “It’s way too young for me.”

“If they really like you, they could change it for you.”

“It’s been a while since they’ve done that,” I said. There had also been a time when people wouldn’t even make me audition.

As soon as I signed in to the Catch That Kid audition, I noticed something was wrong. Every other girl there was at least three years younger than I was. None of them had breasts or braces, like I did.

I’d pass newsstands and see my peers Scarlett Johansson and Kristen Stewart on magazine covers, looking immaculate

The part went to a younger actress, a sullen but cute tomboy named Kristen Stewart. The next year, she would land another of the few parts I ever actually wanted, Melinda Sordino in the adaptation of Laurie Halse Anderson’s book Speak. I had all but begged for that part. I couldn’t understand it. I had always thought it would be me giving up acting, not the other way around.

Something didn’t make sense, at least until I was called for a role in a pilot about girls at a boarding school. I would be playing “the fat girl”. There was a fat joke on every page. “We’d be putting you in big clothes to make you look bigger,” the casting director reassured me. I nodded, but what I really wanted to ask was why they hadn’t called me in for one of the other characters, like Becca. She was funny and quirky. She was also neurotic, and I knew I could play neurotic. Then I saw a head shot of the most beautiful girl I had ever seen. Right by her name, there was a Post‑it note marked: “Called back for Becca!”

That’s when I understood. Things had changed. At 13, being pretty mattered – and not just in the world of movies and TV. The pretty girls at school had always had an air of superiority, but once we hit puberty, they seemed to matter more. My career was the only thing I had over them. Now that it was waning, I was just another weird, nerdy, loud girl with bad teeth and bad hair, whose bra strap was always showing.

***

After a year of no callbacks, my father said what we had both been thinking: “Maybe you should just focus on school right now.”

It meant having to pass up some great scripts – like an “experimental” comedy series called Arrested Development – but it was the right move. I didn’t know who I was without film sets, casting directors and constant rejection, and I needed to find out.

At 16, I expected I would go back to acting at some point. Thinking about life without it made me anxious. But I knew by then that if I wanted to be in film, I had to be beautiful. It would happen, I was sure. For now, I was a teenager and I was allowed to be awkward. A lot of child actors reappeared after puberty, like butterflies from cocoons, fresh‑faced and ready for Neutrogena ads.

Then I opened a magazine and saw a familiar face. A few years earlier, I had met a friendly 12‑year‑old girl with red hair called Scarlett at a press conference on child acting. When a reporter asked if any of us had trouble with the kids at school, she’d said she had been teased so badly she had transferred to a special school for child actors. She had done much better and made lots of friends.

After the press conference, I tried to talk to Scarlett more. I wanted to ask her what had happened at her school, and how I would know if I should transfer. Instead, I watched her pull a balloon off a display, suck in the helium, and sing, “We’re the Chipmunks! C‑H‑I‑P‑M‑U‑N‑K‑S!” It made me like her more.

But the magazine spread was the first I’d seen of her since. There was Scarlett, looking beautiful, talking about her role in a film with Bill Murray, and she was most definitely a woman. She was in grownup movies now, being sexy. How had she done it?

Headshot, aged 11. Photograph: Courtesy of the author

There was a sinking feeling in my stomach. Scarlett was only two or three years older than me. There was no way I was going to become even half as beautiful as she was in that time. Even with my braces off, with contact lenses and a better haircut, I was always going to look the way I did. I knew I wasn’t a gorgon, but I guessed that if 10 strangers were to look at a photo of me, probably about four or five of them would find me attractive. That would not be good enough for Hollywood, where an actress had to be attractive to eight out of 10 people to be considered for even the homely best friend character.

The real world was more forgiving. Plenty of boys were interested in me and it got easier at New York University where I fell in love with Sam, a film student with curly dark hair and warm brown eyes. But my appearance anxieties were always there, and my past was never gone. I did a “where are they now?” interview for an entertainment TV show, but they never aired it because they said I looked “too pale”. I’d pass newsstands on my way to class, wearing pyjamas, and see my former friends and peers – Hilary Duff, Scarlett Johansson and, inevitably, Kristen Stewart – on magazine covers, looking immaculate.

I didn’t know what I wanted, but whatever it was, I wanted it to be my choice. I didn’t want to stop acting because I was too ugly.

“Maybe I should just get plastic surgery,” I said to Sam. Sometimes I secretly wished for an accident where I’d injure my nose and jaw so I could get guilt‑free reconstruction.

“If you want to, you can,” he said, shrugging. “But I want you to know I love you the way you are. You’re beautiful.”

I tried to believe him, but it was as if he were pouring water into a glass with a hole in the bottom. It took a toll on our relationship. In the last fight before our breakup, he told me, “Mara, the one thing I could never stand about you is how much you put yourself down.”

***

There are things I like about the way I look: my eyes are a pretty mix of green, blue and grey, and now that I’ve had time to get used to them, I’d have to concur with Lucy that boobs are fab. It takes a long time to break an old habit, though, and I’m still critical of my appearance, still halfway convinced I’m irredeemably ugly.

I asked the author of a list of Ugliest Former Child Actors why she was punishing other women for the way they looked

Every week or so, a well‑meaning friend or fan sends me an article. Below some variation of “What Do They Look Like Now?” there is inevitably an unflattering photo of me and hundreds of comments. Some are delighted, schadenfreudic: I was once paid to be cute, but now the child actor curse has caught up with me. Others seem angry. My image belongs to them and they aren’t happy that I don’t match up to what they pictured. This type is the most likely to give advice: I should colour my hair, lose weight, go die in a hole somewhere.

I used to feel compelled to respond. Once I contacted the author of a list of “Ugliest Former Child Actors” to ask her why, as a woman, she was punishing other women for the way they looked. She wrote back immediately to apologise. “I write stupid things on the internet to pay the bills,” she said. “I can’t afford integrity.”

The ones who are most critical seem to be normal people who are deeply unhappy with themselves. They want someone else to tear down, and people like me are considered public domain. I understand that celebrities have a contract with the public: they get to be the target of jealousy and criticism, and sometimes admiration, in exchange for money and recognition. But I let that contract run out a while ago. It is not my job to be pretty, or cute, or anything that someone else wants me to be. So the next time someone hiding behind a username decides to tell me what would make me prettier, I’m going to propose the following: I will meet them in person and ask them to listen. I will tell them about going through puberty in the public eye after my mother died of cancer. I will tell them how it feels to find a website advertising nude photos of yourself as a 12‑year‑old. I will tell them I’ve looked at “cute” from both sides now, and in both cases it just made me miserable. I will tell them how fitting it is that the only real acting I do these days is voiceover, where no one can see me. I will tell them how my mother wanted me to prove myself through my actions and skills, rather than my looks. Now I believe I have, and I am happier than ever.

After all that, if they still insist on telling me how I should look, I will consider taking them on as my stylist.

This is an edited extract from Where Am I Now: True Stories Of Girlhood And Accidental Fame by Mara Wilson, published by Penguin Books at £12.35.