By now you probably know that almost the entire cast of Bryan Singer’s X-Men: Days of Future Past surprised Comic-Con attendees today.  Just prior to their Hall H appearance, the cast members participated in what might be a Guinness World Record for press conferences.  Attending were director Bryan Singer, writer Simon Kinberg, producers Lauren Shuler Donner and Hutch Parker, plus cast members Evan Peters, Peter Dinklage, Nicholas Hoult, Jennifer Lawrence, Michael Fassbender, James McAvoy, Hugh Jackman, Patrick Stewart, Ian McKellen, Halle Berry, Shawn Ashmore, Ellen Page and Omar Sy.  It was an amazing once-in-a-lifetime event to witness all of that talent on one stage, although fans will be privy to the experience once X-Men: Days of Future Past hits screens May 23, 2014.  Hit the jump for highlights from the press conference.

On the adaptation of the source material:

• Kinberg: The biggest difference between the film and the source material is that Kitty’s not the one who goes back in time, she sends someone back in time.
• Singer: Initially, it began with the goal of bringing this cast together and time travel or time displacement of some kind would be  the tool we could use to do that. Essentially the Wolverine of the future … his consciousness is sent into his younger self, and it’s nice that Hugh is able to play both parts, because his character is ageless, which is really unique.

On returning to play their characters and “old” meeting “new” X-Men:

• Stewart: The best part of this movie is knowing that, at an earlier time in my life, I was James McAvoy.
• McAvoy: And if I’m going to grow up to be someone, who better than Sir Patrick Stewart?
• McKellen: I’m looking forward to being as dashing and successful as Michael Fassbender.  [Gesturing to Stewart] We still can’t believe our luck, that we’re still allowed out. [laughter]
• Singer: I brought the old hallways from the X-Men, 2 and 3 … Jen was standing in the hallway and we were looking at one of your costumes and you were like, “Can I see Cerebro?” And I said, “Sure. I’ll show you Cerebro.”
• McAvoy: That’s not a euphemism. [laughter]
• Hoult: When you walked into those old corridors for the first time, I looked over and saw Jackman was Wolverine and I kinda panicked.  Those were films I grew up on.
• McAvoy compares the first time he saw the Aslan prosthetics from Narnia to his approach to the iconic comic and film series of X-Men.

On changing the continuity of the film series:

• Singer: Of the universe as established in the movies? Yes, there will be some of that … I do believe in some continuity, but things will change. That’s the nature of time travel.

On interaction between older and younger versions of characters in the same scene:

• Singer: Primarily since Wolverine is the journeyman, his interaction with the younger cast is primary. There will be a moment … where these two characters come face to face, the younger self and older self.  We’re trying to do it in a unique way.
• Jackman reflects on his first American film - Singer’s X-Men - and the reality of coming back 14 years later to reunite with the cast members.  He counts himself lucky to work with casts from both film series.

On their reaction to the idea to bring the two timelines of the X-Men films together:

• Stewart: I heard about this movie and I was immediately filled with such sadness, because, as you may recall, at the end of the third movie, I was vaporized by Jean Grey. [laughter] And that really hurt, by the way. I hope that never happens to any of you. So, I assumed everyone - Hugh, Halle, Ian - they’d be back, but it wasn’t me.  Then, something happened … which I’m not allowed to talk about. Am I? Oh, you can!
• Singer: Characters come back to life in the comics. Whenever I do something, I can’t just do it flippantly, I have to believe in the idea, the conceit. In my own mind, I understand how Xavier is alive from X-Men 3. There’s a beat after the credits when his conscious is alive in a woman in the hospital. So, you take that, mix it with some powerful mutants - mutants can do a lot of cool stuff - and you can imagine… anything’s possible.
• Stewart: So does that mean Xavier is back?
• Singer: For the moment … Another thing about this movie that’s different from the other X-Men movies, there’s a science-fiction aspect as well.  There’s technologies, there’s the Sentinel program which is something that’s going to be part of the picture. So the time travel element and the science-fiction element is something that hasn’t been explored before.

On costumes:

• Lawrence: [Gestures to Berry] She’s pregnant, I’m naked. Come see the movie. [laughter]
• Singer: This Mystique is less innocent, evolved, getting closer to where Mystique was in X-Men 2.
• Lawrence: At the end of the last movie, she ended up “mutant and proud” after being covered up at the beginning.
• McAvoy: My threads are awesome; lots of flair, chunky shoes, psychedelic shirts, lot of brown jackets going on.
• Jackman: In the future, the X-Men suits are unbelievable. First of all, hell of a lot more comfortable to wear than X-Men 1 and 2, but they look really amazing. People in the future wear suits who have never worn suits before. That’s all I’m going to say.
• McKellen to Fassbender: Do you get to wear the helmet?
• Fassbender: Yes.
• McKellen: The best thing about playing the old Magneto is: no helmet.
• Fassbender: You don’t like the helmet?
• McKellen: Oh, no. We’ll talk about our helmets another time.