What's so fun about talking to someone like Elizabeth Olsen about something as huge and important as "Avengers: Age of Ultron," is that it's clear she's not used to not be able to talk about stuff. The star, who famously starred in "Godzilla" last summer, which had an air of mystery but nothing like the behind-several-locked-doors secrecy of a Marvel movie, seemed genuinely befuddled, as the tried answering question after dweeby question without spoiling anything or getting herself (or others) in trouble. It was one of the more endearing qualities of a movie star made almost exclusively of endearing qualities.

In "Avengers: Age of Ultron," Olsen plays Scarlet Witch, a character more closely associated with the X-Men, but clearly a big part of Avengers lore as well. Her human name is Wanda Maximoff, the twin sister of Pietro Maximoff aka Quicksilver (played in the film by Aaron Taylor-Johnson). Instead of having powers involving punching, kicking, or flying, the Scarlet Witch's powers involve telekinesis, mind-control, and telepathy. One of the cooler powers (that she fully exploits) is her ability to get into the head of the other Avengers, once again played by Robert Downey Jr., Scarlett Johansson, Mark Ruffalo, Chris Evans, Chris Hemsworth, and Jeremy Renner.

Like Aaron Taylor-Johnson, the first question lobbed Olsen's way was about her character's distinctive accent. "Can I talk about it?" she asks, seemingly to the unit publicist (who bears a striking resemblance to Mark Ruffalo) but also to us. "We know that we're from Eastern Europe and it's something that we got to create. It's a make-believe place, so its something that Aaron and I, with the dialect coach kind of created together." When asked what the country is, she said, "I can't talk about it."

Some will remember that we actually got to see Scarlet Witch and Quicksilver, for a few seconds, at the end of last year's terrific "Captain America: The Winter Soldier." Olsen said that the sequence, which featured them contained in some kind of bunker, would be continued. "There is definitely a connection that is very evident," she said. But when asked if the two characters share ideas as is hinted at in that sequence, she nearly breaks down into an inaudible string of garbled English: " I don't know. I think there's a bit of all of it, you know. I think it's, it's interesting, I don't know what I can tell, but like it's, ah, it's..."

Olsen was more forthcoming about the powers she gets to use in the film, including the whole invasive mind power shtick. "Yeah, so I am able to go into someone's head and they'd never see. I can feel and see what they feel and see, so it's not just me manipulating them. But what I love about her is that in so many superhero films, emotions are kind of negated a bit, but for her everything that someone else could feel, like their weakest moments, she physically goes through that same experience with them, which is pretty cool." She then confirmed the exploitation of the heroes' fears: "Yeah, she can, if they have the biggest, darkest fear, I get to see that."

Not that she's only playing head-games, since she gets in on the action too: "I can control energy. I can manipulate energy away, so that's what the red stuff is that we're playing with." When asked to elaborate on the physicality of her character, she did so: "It's been so fun, because you can't be like, well, How does this magic witch hero move? Like, there's nothing physically that you can just reference from dance or, you know, martial arts or anything like that. So we started off with Joss kind of having these ideas based off just images in the comics of what the hand gestures would look like or the arms look like, and then I work with a dancer and so the two of us get locked up in a room together and we move and we try and figure out what looks strong and where the energy comes from. But also in the film, I'm having a journey of discovering how powerful she can be. So we've got to start somewhere. We've got to figure out what all those different levels are." She then described how different her choreography is: "It's funny, because everyone's doing stunt practices and choreography and she and I are just like doing weird dance moves and pretending like we're making things shoot out of our hands."

Olsen's character is also the latest in a long line of Joss Whedon heroines, dating back from "Buffy the Vampire Slayer" and continuing through more recent works like "Dollhouse" and, of course, Black Widow in the last "Avengers." "You feel like you're in good hands and the cool thing is that he hasn't been able to create these characters. He's been given them from other directors or writers, from their other franchises, and he's been adapting, taking what has already been created and serving them in Avengers," Olsen explained. "And in this, he's able to create Wanda, and he's such a huge fan of her and it's really awesome to get to have that. I think he is enjoying also getting to have the experience where he gets to create it, because he is such a fan of, of creating these strong, amazing women."

She also said that, even though she didn't get to work with her much, she was thrilled to contribute to the vibe Johansson's Black Widow was going for. "It's nice to have that kind of, there's obviously Black Widow, but it's nice to have another strong presence. Usually, I haven't really been around when Scarlett was working, so I kind of feel like the only female most of the time. And it's nice to have a stronger presence instead of a weak one or like an office one or something." Nobody puts Lizzie Olsen in an office!

There was a lot of discussion on the set about Whedon continually tweaking or trying out new dialogue, sometimes on the day of filming. This kind of thing is unprecedented, especially for a project of this scale. When asked if Whedon tweaked a lot of her contributions, she shot back, "No." Olsen then continued: "If there are and then we have script changes where we'll come on the set shooting a scene and he'll be like oh, by the way, I added a scene right before this. And you're like, what? And then that scene changes your full opinion of what you're about to shoot, but that's okay. You can change your mind really quickly. And so that's the only thing, while we've been shooting, as the script has been changing, but nothing that you ever feel unprepared for."

In fact, the only thing that Olsen could feel prepared for, is answering questions that she's not supposed to. When we asked what her relationship was to Ultron (James Spader), the villainous robot at the heart of the new movie, she said, curtly, "I think our relationship to Ultron will not be shared." Then she laughed. And we laughed with her.

"Avengers: Age of Ultron" hits theaters May 1.