"I thought it was a fitting end to a story that has affected so many people. I thought it was very endearing, innocent and wholesome in the way that it keeps those characters in their time," Atwell tells The Hollywood Reporter.

Atwell is back in theaters this weekend with Blinded by the Light, a film from Bend It Like Beckham director Gurinder Chadha, which tells the true story of a British-Pakistani kid who becomes enamored with the music of Bruce Springsteen. Atwell plays Ms. Clay, an encouraging teacher to Javed (Viveik Kalra).

In a conversation with The Hollywood Reporter, Atwell discusses her inspirations for Blinded by the Light and weighs in on Marvel's animated What If? series, which will see her reprise her role as Peggy Carter.

While it’s an unimaginative first question, were you a Springsteen fan before this film?

I came to Springsteen’s music through his song "Streets of Philadelphia." He was mostly before my time, but as a huge Tom Hanks fan, it wasn’t until Philadelphia, which Bruce won an Oscar for, that I found out a little more about his music. Hearing his music during the filming, of course, I knew all his songs already. They’re part of the wiring in my brain of musical knowledge. I wouldn’t necessarily be able to distinguish many of his lesser known ones, but I’m aware of his big hits.

Your character, Ms. Clay, is the first person to really recognize the writing talent of the lead character, Javed (Viveik Kalra), as well as the circumstances he’s dealing with at home. Did you have a Ms. Clay in your own life that helped you overcome any doubt about your own talent?

No one sticks in my head, but I had lots of really strong teachers in my comprehensive secondary school in London, who were all women. At different points in my drama school education, there were people who stood out to me, I suppose, but there was a kind of an amalgam of qualities in various teachers that I liked. You could have a teacher be really nice to you one day, and then criticize you the next day for not doing the homework. There wasn’t an overriding person who was this idealistic version of what I wanted a teacher to be. Teachers are human; they’re not all perfect. What I liked about Ms. Clay on the page is that she believed in Javed but in an unsentimental way. She has the ability to give constructive criticism where she criticizes the work, but not the person, which is what I really liked when I read it. To me, critiquing a student’s work — knowing they’re very vulnerable and impressionable — and doing the utmost to not break the spirit of that person while you’re trying to guide them along, is the mark of a good teacher. A good teacher helps that child create standards for themselves and themselves alone, that they need to work towards, without comparing themselves to how anyone else is doing. Knowing how to give each individual child a push in a kind way is a very difficult thing for a lot of teachers to do.

Conversely, have you found yourself being a mentor-type figure to young or aspiring actors you encounter?

I don’t look to become that. To label yourself as a role model or someone to be looked up to inevitably means that you’re going to fall in some way or fall short of their expectations. I heard a quote the other day that I really liked, "Two ways to dehumanize someone is to ignore them or to idolize them," and I thought that feels very true. If you put someone above you or below you, you’re basically saying that they’re not of equal standing. So I don’t really think about any of those things, but I’m certainly happy and open to offer a suggestion if someone asks me for something specific that helps them. I don’t think one should ever give advice unless that person is asking for it.

Was there a musician or group that spoke to you in a way that is similar to how The Boss spoke to Javed in this movie?

Growing up I loved David Bowie and Joni Mitchell. Now I love Florence and the Machine. There’s something wild about her that I find fascinating and captivating to listen to and watch. There’s no one that I would listen to and go, “Oh, this is my philosophy in here, and it’s going to transform the way that I see the world.” I think growing up in London meant that I was exposed to a lot of rich culture from all walks of life. Rather than the one person that was my favorite out of the limited world I grew up in, I did kind of the opposite; I was so immersed in West London’s world music, whether that’s from the West Indian cultures or the Notting Hill carnival… I went to school with lots of students who were originally from the Caribbean, so a lot of reggae music was important growing up. My dad was also very much into folk so I’d listen to a lot Joni Mitchell and Neil Young. My mom was also into David Bowie and Led Zeppelin, so I got that kind of vibe from her. So, I felt like I was constantly shifting, whether it’s ‘90s R&B music or Sondheim musicals. (Laughs.) So, I feel lucky enough to be exposed to a variety of music.

Was there anything unusual about this particular casting process?

I came to the production fairly late and fairly quickly. The offer came in, I read the script, I liked the tone, I liked [director] Gurinder [Chadha] and I had a sense of what she would do with it and what I could do with Ms. Clay... It was just a very joyful week, or less than a week, a few days, really. I was led by the script.

When you arrive on set, do you already have your performance in mind, or do you not commit to anything until you’ve accounted for all the on-set variables?

I’ve tried lots of different things in the past, and I’ve tried to be very prepared. If I’m doing a period piece, I’ll learn a lot about the historical context. If the character comes from a very particular area of the country that I don’t know much about, I’ll research that. With someone like Ms. Clay, who’s not based on anyone specific to my knowledge, Gurinder was like, "I like the qualities that you bring naturally as to who you are…" I feel that you have to be open and present to the environment that you’re in, and having a rapport with the director, where you’re hopefully trusting the vision that they have, means giving them options so that every take feels different. You can go in one direction, and then you can pull it back. Something can be more comical, more thoughtful, more romantic, more active and strong… That’s part of my training as a theater actor… but since you don’t get six weeks of rehearsal time on a film set, sometimes it’s turning up and doing what feels most comfortable and natural — without being in my head. You can be slightly more pliable, flexible and dynamic with what everyone is doing if you’re not stuck in a certain way of delivery. I also like to play with the other actors and deliver a line differently. If they respond slightly differently, then I know that I’m working with a really great actor because they’re able to not just be in their own head, controlling their performance, but they’re able to bend to be with their co-star. I think that’s what makes for a much more fulfilling experience of working on set.

Shifting gears, when did you learn that Peggy Carter would comprise the final shot of Avengers: Endgame, essentially closing the book on this era of Marvel movies?

I think we shot that maybe two years ago. So, it was maybe a few weeks before then that I got the call saying, "We’re thinking about this… What do you think about it? It might end the whole franchise." Then, it was an afternoon of filming about two years ago.

What was your first reaction?

I thought it was a fitting end to a story that has affected so many people. I thought it was very endearing, innocent and wholesome in the way that it keeps those characters in their time. I thought it was quite beautiful and very tasteful of Marvel to finish this 10-year story in a very simple storyline about two human beings — and one of them doesn’t even have any superpowers. So, I thought the tone of it, to end there, after some extraordinary things of trauma, action, effects and powers… to just have two people slow-dancing was very beautiful.

Did you film more material that didn’t make the cut?

No, we filmed just those two things. You see me through the office blinds, and then that scene with the slow-dancing. Those were the two that I was always intended to film.

It was just announced that you’ll be reprising Peggy Carter for Marvel’s What If…? animated series. How long have you been sitting on this news?

It kind of slipped on. What’s remarkable is that this is a couple of work days for me. I’ll do half an afternoon on Endgame, or then you’re in the studio for a couple of hours on What If…? Because so many fans love this franchise, it’s so much bigger than the time that affected my actual life, which is a remarkable thing. So, it just means that I can’t really remember the details of when exactly it was, but I want to say a few months, maybe.

You’ve appeared as Peggy Carter in five films, 20 episodes of television and one short film. If you never get to play Peggy in live action again, do you feel fulfilled? Do you think you’ve explored her as much as you possibly can?

Oh, yeah! I feel really fulfilled. It was a great time, and I think they ended it beautifully with Endgame. It feels like a fitting end to that narrative. I’m a classically trained theater actor so I want a stab at the challenging parts in the canon for theatrical actresses. That’s something that I’ve always aspired towards. So, I feel lucky to have played her, but she’s one aspect of my career. She’s one part that I’ve played. With every job that I’ve done, I’ve taken the job because I’ve seen something within the character that I’d love to explore or try and be challenged by. With a leading part, it requires a lot of my focus and passion, but it’s the same focus and passion whether it’s Peggy Carter or it’s Rebecca West in Rosmersholm on stage, which I just finished. It’s the same curiosity to see what each character’s world is.

Did your relationship with Disney via Marvel help fast-track your Christopher Robin casting?

Good question! Marc Forster, who directed it, hadn’t seen me in anything I don’t think. I spoke with him via Skype while I was on the back of jet ski during a vacation. It was the only time we could meet, and he laughed when I answered his FaceTime on my phone and I was in a life jacket on a speed boat going, "Hello? I’m trying to get reception because I’m on an island." He loved that and thought it was very funny; it kind of broke the ice between us. So we quickly built quite a bit of rapport. I don’t really question those things or ask those kinds of questions like "Did I get this because of this?" I certainly didn’t know Brigham Taylor, who’s the executive producer, or producer Kristin Burr. I didn’t know Marc, so I don’t know what was said or discussed between them and my agents. I’m not really privy to those conversations. It felt like two different kind of things.

What can you say about your role on Netflix’s Criminal [which premieres on September 20]?

Essentially, there were 9- to 11-page monologues at one point, which you don't often get to do onscreen. I liked the idea of the premise being the same police characters, the same location but every episode is a different guest star coming in for an interrogation. I thought that was quite interesting, and also the fact that my character was brought up in modern-day West London. She’s gone through this thing where you don’t know whether she’s responsible for this crime or not. It keeps you guessing as you go along, and there’s an emotional core to some of the scenes, which I thought were going to be a challenge but could also give her a bit of depth. The challenge of shooting these 9- to 11-page monologues in five days on a soundstage was the attraction for me.