You know you're not going to win. You're seated in second-class. You've trodden on someone's dress. Author Neil Gaiman on what it's like to be invisible at the Oscars

There were authors grumbling about not going to the Oscars. I heard about it from friends. "So why are you going?" they asked.

I had written a book called Coraline, which the director Henry Selick had transformed into a stop-motion wonderland. I'd helped Henry as much as I could through the process of turning something from a book into a film. I had endorsed the film, encouraged people to see it, mugged with buttons on an internet trailer. I had also written a 15-second sequence for the Oscars, in which Coraline told an interviewer what winning an Oscar would do for her. I'd assumed that would get me into the Oscars. It didn't. But Henry, as director, had tickets and could decide where they would go, and one of them went to me.

My father had died on 7 March 2009. This year's Oscars are on 7 March. I expect it will be just another day, and it will not bother me at all, demonstrating that I do not know myself very well, because when the day arrives I am melancholy, and do not want to go to the Oscars. I want to be at home, walking in the woods with my dog, and if I could simply press a button and be there without disappointing anybody, I would.

I get dressed. A designer named Kambriel, whom I met when she had made a dress that would allow my fiancee and Jason Webley to represent conjoined twins, had offered to dress me for the Oscars, and I took her up on it. She made me a jacket and a waistcoat, and I fancy that I look pretty good in them. Best of all, I now have an answer to the people who ask, "What are you wearing to the Oscars?" And it makes Kambriel amazingly happy.

Focus Films, which distributed Coraline, is looking after me. The night before the Oscars, they had a small reception at the Chateau Marmont for their two nominees, Coraline and A Serious Man. The partygoers were a strange mash-up of Minneapolis Jews and animators. Even more oddly, I was one of the Minneapolis Jews (or almost – I wound up comparing notes with one of the other partygoers on the St Paul newspaper's pulse-pounding exposé that I actually live an hour away from Minneapolis).

The best thing about the Oscars, I realised when the nominees were announced, is that Coraline won't win best animated picture. Nothing but Up can win best animated picture.

A limo picks me up at 3pm, and we drive to the Oscars. It's a slow drive: streets are closed off. The last civilians we see are standing on a street corner holding placards telling me that God Hates Fags, that the recent earthquakes are God's Special Way of Hating Fags, and that the Jews Stole something, but I can't see what, as another placard is in the way.

A block before we reach the Kodak Theatre, the car is searched, and then we're there and I'm tipped out on to the red carpet. Someone pushes a ticket into my hand, to get the car back later that night.

It's controlled chaos.

I am standing blankly, realising I have no idea what to do now, but the women look like butterflies, and there are people in the bleachers who shout as each limo draws up. Someone says: "Neil?"

It's Deette, from Focus. "I just came back from walking Henry through. What a nice coincidence. Would you like me to take you through?"

I would like that very much. She asks if I would like to walk past the cameras, and I say that I would, because my fiancee is in Australia and my daughters are watching on TV, and Kambriel will be happy to see her jacket on television.

We head down into the throng, behind someone in a beautiful dress. It looks like a watercolour of a dream. I have no idea who anyone is, except for Steve Carell, because he looks just like Steve Carell on television, except a tiny bit less orange.

We are scrunched together tightly as we go through metal detectors, and the beautiful watercolour dress is trodden on, and the lady wearing it is very gracious about this.

I ask Deette who's inside the dress, and she tells me it's Rachel McAdams. I want to say hello – Rachel's said nice things about me in interviews – but she's working right now. I'm not. No one wants to take my photo, or, Deette discovers, to interview me. I'm invisible.

At the bend in the red carpet we pause. I look down at Rachel McAdams's watercolour dress and wonder if I can see a footprint. Cameras flash, but not at me.

And we're into the Kodak Theatre. Someone else introduces me to the editor of Variety. I realise my facial recognition skills do not work when people are in tuxedos. (Except for James Cameron, whom I have now only ever seen in a tuxedo and would not recognise wearing anything else.) I tell this to the editor of Variety. He points to a man with a tan and a huge grin, tells me it's the mayor of Los Angeles. "He comes to all these things," he says. "Why isn't he behind his desk, working?"

"Er. Because this is the biggest day in Hollywood's year?" I venture. "And it's Sunday?"

"Well. Yes. But he still comes out for the opening of a drinks cabinet."

I had been to the Golden Globes six weeks earlier and discovered that the commercial breaks in award shows are spent in a strange form of en masse Hollywood speed-dating as people shuttle around the room trying to find friends or make deals, and assume that tonight will be much the same.

The Kodak Theatre has a ground floor and, above that, three mezzanines. My ticket is for the first mezzanine. I head, sheep-like, up the stairs. There is a crush to get in, as a disembodied voice tells us urgently that the Academy awards will start in five minutes. I stare at the woman in front of me. She has blond hair and a face that's strangely fish-like, a scary-sweet plastic-surgery face. She has old hands and a small, wrinkled, husband who looks much older than her. I wonder if they started out the same age.

And we're in, with no time to spare. The lights go down, and Neil Patrick Harris sings a special Oscars song. It does not seem to have a tune. Several people on Twitter who aren't sure which Neil is which congratulate me on it.

And now our hosts: Steve Martin and Alec Baldwin. They come out, they make jokes. From the first mezzanine, the timing is off, the jokes are awkward, the delivery is wooden. But it doesn't feel as if they're playing to us. I wonder if it works on television, and send the question out on Twitter. A few hundred people tell me it's just as bad on TV, 20 tell me they're enjoying it. I decide this is what Twitter is for: keeping you company when you're all alone on the mezzanine.

Best animated movie is the second category of the night. My 15 seconds of Coraline talking to the camera goes by fast. There, I think. The largest audience that my words will ever have. Up wins.

The Oscars continue. In the audience, we cannot see what they are seeing on television at home. Somewhere below me George Clooney is grimacing at the camera, but I do not know.

Tina Fey and Robert Downey Jr present the best screenplay award, and are funny. I wonder if they wrote their own bit.

During the commercials, the lights go down, and they play music to mingle by. Roxanne does not have to put on the red light.

I head for the first mezzanine bar. I'm hungry and want to kill some time. I drink whiskey. I order a chocolate brownie that turns out to be about as big as my head and the sweetest thing I've ever put in my mouth. I share it.

People are wandering up and down the stairs.

Whiskey and sugar careening through my system, I defy the orders on my ticket not to photograph anything, and I tweet a picture of the bar menu. My fiancee is sending me messages on Twitter urging me to photograph the inside of the women's toilet, something she did during the Golden Globes, but even in my sugar-addled state, that seems a potentially disastrous idea. Still, I think, I should head downstairs and, in the next commercial break, say hello to Henry Selick. I walk over to the stairs. A nice young man in a suit asks me for my ticket. I show it to him. He explains that, as a resident of the first mezzanine, I am not permitted to walk downstairs and potentially bother the A-list.

I am outraged.

I am not actually outraged, but I am a bit bored, and I have friends downstairs.

I decide that I will persuade the inhabitants of the mezzanines to rise up as one and to storm the stairs, like in Titanic. They might shoot a few of us, I decide, but they cannot stop us all. We can be free; we can drink in the downstairs bar; we can mingle with Harvey Weinstein.

Someone tells me on Twitter that nobody's checking the elevators. I suspect that might be a trap, and head back to my seat.

I have missed the tribute to horror movies.

Rachel McAdams presents an award in her beautiful, oh-so-treadonable dress.

For the best actor and actress awards, a tableau of people who have worked with the nominees tell us how wonderful they are. I wonder if it works on TV. On the stage in front of us, it is painfully clumsy.

People below us are milling and chatting and schmoozing more with every commercial break. There is an edge of panic to the disembodied announcer's voice as she orders them back to their seats.

The man in the bar who reminded me of Sean Penn turns out to have been Sean Penn. Jeff Bridges's standing ovation reaches all the way to the top mezzanine. Sandra Bullock's standing ovation only reaches the front rows of our level and stops there. Kathryn Bigelow's standing ovation covers the entire hall except, for some reason, the top right of the first mezzanine, where I am sitting, where we remain sitting and clap politely.

It all seems to be building up to a climax, and then Tom Hanks walks out on to the stage and tells us, with no build-up (if you exclude months of For Your Consideration campaigning) that oh, by the way, The Hurt Locker won best picture and goodnight. And we're out.

Up two escalators to the governors' ball. I sit and chat to Michael Sheen, who brought his 11-year-old daughter, Lily, about the sushi dinner we had two days before, interrupted and ended by a police raid. We still have no idea why. (Next morning, it will be a front-page story in the New York Times. They were serving illicit whale meat.)

I see Henry Selick. He seems relieved that awards season is over, and that he can get on with his life.

I feel as if I've sleepwalked invisibly through one of the most melancholy days of my life. There are glamorous parties that evening, but I don't go to any of them, preferring to sit in a hotel lobby with good friends. We talk about the Oscars.

The next morning the back page of the Los Angeles Times Oscar supplement is a huge panoramic photograph of the people on the red carpet. Somewhat to my surprise, I see myself standing front and centre, staring down at Rachel McAdams's beautiful watercolour dress, inspecting it for footprints.