Here's a roundup of the juiciest tidbits:
Shailene Woodley on getting into the Divergent action: "Green-screen acting is way more difficult than working with people. It was really fun. I’ve never done a movie with themes this big in a world that’s different than ours. I had to erase some of my preconditioned acting styles and create a new world and adapt to this film’s style. Veronica [Roth] created such a great world and Neil [Burger] brought it to fruition in a way I could never have imagined."
Divergent author Veronica Roth on her novel, faith and philosophy: "I’ve always thought of Divergent as a kind of indictment of myself. If I were arranging a utopia, it would be a world where everyone is responsible for their own actions. But the book is basically an example of why I shouldn’t be a god."
Theo James on why his character in Divergent is like Paul Newman: "He had a grounded, quiet masculinity which you don’t really see much these days. The kind of Paul Newmans... the strong sense of masculinity without having to show it as well having a strong sense of being and intelligence."
Harrison Ford on Ender's Game author Orson Scott Card's gay-marriage comments: "I don't think that issue rears its head in the work. No part of the story concerns Mr. Card's theories about society in terms of gay issues or homosexual issues. So I hold it completely separate. I think it's an imaginative and complex story. And I'm glad he told it. And I'm glad I had a chance to be a part of it. I think he has a right to his opinions. I am aware of his statements admitting that the question of gay marriage is a battle that he lost. And he admits that he lost it. I think we all know that we've all won — that humanity has won, and I think that's the end of the story."
Ford comparing Han Solo to his Ender's character: "Ender doesn't really face so much the issues of morality until the end of the film, when he knows what's happened to him, but Graff is aware of his moral responsibilities all through the novel. It's part of the story. I think the book deals with a lot of very complex issues of social responsibility and the moral issues that one faces when one is part of a military establishment. I was delighted to be involved in a film of such high ambition with such talented people. I think Graff is a much more complex character than Han Solo, which doesn't mean that I regret Han Solo."
Watch our red-carpet interviews with the movies' casts: