The pleasures of Marvel’s Doctor Strange are, first and foremost, visual. Here is a movie of incredible images and bizarre sights. In comparison to its mind-boggling special-effects sequences, the movie’s characters sometimes feel a little flat and generic. I sometimes found myself wanting the people onscreen to stop talking so they could take us on another wild trip through the multiverse.

The exception to this rule is the Ancient One, an all-powerful wizard played by Tilda Swinton. The British actress has won an Academy Award, for her role in Michael Clayton, and appeared in mainstream fare like The Chronicles of Narnia series and Trainwreck, but she tends to weave her magic in more offbeat fare like I Am LoveWe Need to Talk About KevinOnly Lovers Left Alive, and Snowpiercer. Swinton brings that peculiar energy to her performance as the Ancient One, who lives in a temple in Kathmandu, training an army of mystical warriors (and, eventually, Benedict Cumberbatch’s Stephen Strange) to defend the Earth from extra-dimensional threats.

The Ancient One character was originally conceived by Stan Lee and Steve Ditko as a decrepit Asian man; the recasting of the character as a youthful (if bald and scarred) white woman has received criticism from some critics, and not unfairly. But Swinton is also really good in the role; few people alive today could have pulled off the character’s combination of wisdom, mystery, butt-kicking, and dry humor. Swinton has a way of surprising you onscreen, and she surprised me in our phone conversation as well, particularly when she randomly quoted (and then confessed her love for) the Will Ferrell comedy Talladega Nights. I’m not sure the Ancient One would approve of its “If you’re not first, you’re last” philosophy, but such is life.

Your Ancient One is obviously different than the one in the comics, so what did you draw on to inspire this version of the character?

The way in which the Ancient One is portrayed in the film started with the script. Scott [Derrickson] told me that he wrote the part with me in mind which made it a very easy thing to say yes to because he wrote something that kind of fitted me quite easily. A very ancient, Celtic person felt pretty close to home. And I thought a lot about how lucky I’ve been in my life to sit at the knee of various, ancient, wise people; from my grandmother and other wonderful mentors. In fact, not even so ancient but just people who’ve kind of gone before and have some kind of perspective that I’ve draw on. 

It was just really enjoyable being this energy which is the opposite to Doctor Strange. Doctor Strange, when he comes to meet the Ancient One, is such a ball of bitterness and rage. He’s all jacked up on Mountain Dew and really miserable and invested in material things. And, so, it was very clear to me that the Ancient One had to be really the opposite of that. So, I went very loose and very light and flexible and kind of irritated the hell of it. He thinks she’s just some flaky, old hippie and then she turns out to be a proper badass.

I’m sorry; did you say you thought Stephen Strange was jacked up on Mountain Dew? 

I was quoting Talladega Nights right there. There’s a moment in Talladega Nights where [one of the Ricky Bobby’s sons says he’s] all jacked up on Mountain Dew.

For some reason, I can’t think of somebody being all jacked up without thinking of them being jacked up on Mountain Dew a la Talladega Nights. Sorry that was just me.

No, I’m glad. I love that you’re as big a fan of that movie as I am.

[laughs] How could I not be?

That’s a very good point. The Ancient One’s fairly mysterious in terms of her background, and that’s sort of how it stays in the whole film. I’m curious: Was there more backstory written for you to draw on, or did you have to come up with your own backstory?

I’m pretty constantly dropping hints in Kevin Feige’s ear about a prequel. I’m constantly harassing him about that. I don’t know if it’ll get anywhere, actually. But, no, really we didn’t think about it at all. In fact, we went out of our way not to, because it’s important that the Ancient One is entirely shrouded in mystery. I suggested the scar on the back of her head, which I like very much because they represent the kind of violence in her past and that she’s a survivor. There’s something very brutal about that and the feeling that she is at least seven hundred if not a thousand years old. If you live that long in the way in which she’s lived, then you can be sure she’s carrying with her a few bruises and scars. So, that was about as far as we got really. But, we kept it nice and oblique even for ourselves.

So you’re already pestering Kevin Feige for a prequel or a spinoff? 

Just leaving the odd hints, you know. Writing little notes and putting them in his pocket. Writing lipstick messages on his mirror. Things like that. Just seeing see how far we get.

You mentioned the Ancient One’s scars. It sounds like you were a little involved in creating the look of the character. Tell me about crafting the visual side of the character and what you contributed.

Well, I was very happily involved in the creation of the look. It was something that we had the luxury of figuring out over the course of a couple months. We tested all sorts of looks. I will say that the bald head was my suggestion from the very beginning and we came back to it at the very end. We could have gone with all sorts of other things but at the end of the day it felt like the freshest and just the keenest combination of the options and at the same time the most modern. And I like the sort of gender-free nature of the character. It just feels like the most ancient old crone you could imagine and also a newborn. Also, of course, it’s quite close to the Sorcerer Supreme, Kevin Feige himself. So that was an influence.

Something I always enjoyed about the Steve Ditko Doctor Strange comics were the way he draws hands and gestures. There’s a lot of attention to that in this film. The spells have these very elaborate gestures. Was there an established language or could you just wave your hands however you wanted as long as it looked cool?

No, there was a very specific language which was designed for us by this proper magician called JayFunk who does extraordinary tutting. I don’t know if you know about tutting but you should go on YouTube and look at JayFunk doing tutting. He’s got really magical fingers. He does all sorts of double-jointed things that nobody else’s hands would ever do.

But, he invented, with a few artists, this language. These movements had to be incredibly precise because we were working alongside the visual effects team. For example, when I was showing Strange how to cast a spell, I’m creating a mandala in the air. My fingers had to be incredibly precise in the frame because that’s where they were going to be drawing the light. And, yes, it was a real science and fascinating to work with.

I read a few interviews where you were talking about being a fan of Marvel for a long time. Maybe not Doctor Strange specifically, but Marvel in general. Do you have any favorite characters or comics?

I’m really excited about Captain Marvel. I think that’s gonna be really something. And, again, look at the way the studio is coming out of a different box every time now. We had this wonderful run with Ant-Man, Guardians of the Galaxy, which I’m a huge fan of. I absolutely love them; it’s probably my favorite Marvel movie apart from Doctor Strange now. I think Doctor Strange is completely fantastic. I’m completely objective about it, I think it’s really awesome. It takes the Marvel Cinematic Universe to a new level and I think that Captain Marvel is going to take it somewhere else as well.

When you’re filming these elaborate trippy sequences, it’s just a bunch of people standing around in front of green screens. What was your reaction to seeing the final product onscreen?

I was in a very fortunate position because of course, nobody saw any of it until now because it was be finished last week, basically. But I got an early opportunity to see it because I was providing voiceover for that first scene. So I saw it develop over several weeks. Every time I thought it couldn’t get more extraordinary and it’s gotten extraordinary and tonight I’m going to see it for the first time in 3D. That’s the next level for me, and IMAX as well, so I’m very excited about that.

It was talked about as this great set piece, the “Magical Mystery Tour.” Of course the amazing thing about this film is that it has several big set pieces. That huge Hong Kong set piece at the end, which is beyond. That was something else, but the Magical Mystery Tour, which is a very ambitious thing to do in a movie, because you got something pretty massive happening in the first quarter of the film. It’s difficult to imagine how they can top it, but they do.

You already talked about wanting to make an entire Ancient One movie. I was going to ask what you thought of the experience of being in the big Marvel Machine, but it sounds like you had a good time with it. 

A super good time. I keep saying, it's like joining the circus. It's just great. Nobody is working for Marvel who isn't a superfan and it's run by the biggest superfan of them all. It's all just a very happy ship.

Doctor Strange opens in theaters on Friday.

More From ScreenCrush