7:41am PT by Hilary Lewis
'X-Men' Star Patrick Stewart on Returning for 'Days of Future Past': 'There's Vaporization and Vaporization' (Video)
Viewers who didn't stay through the credits in X-Men: The Last Stand may be wondering how Patrick Stewart's Professor Xavier is able to return for X-Men: Days of Future Past after being vaporized in the 2006 film.
But Stewart revealed on Thursday's Good Morning America that there's a simple explanation for his reappearance, and it's in that 2006 movie.
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"There's vaporization and vaporization," Stewart said when GMA's Robin Roberts asked how he could return. "And clearly you didn't stay until the end of the credits. In these movies, you've always got to stay until the end of the credits because there's always a little surprise, and that's why I am back in this movie."
He also joked that another castmember needed him to return.
"The reason is that Hugh [Jackman] just couldn't do it without me," Stewart added.
It seems the stars of both the original series of X-Men films and the 2011 reboot First Class really bonded while shooting Days of Future Past, which reunites characters from both iterations.
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"We actually shot the film with the future part first, so it was like a reunion to begin with," Jackman said. "And then it was the younger characters coming in."
James McAvoy, who plays the younger Charles Xavier, said it meant a lot to him to get somewhat of a hand-off from Stewart after they filmed their scenes together.
"When I took over the role, I never thought for a minute we'd be in the same movie together, let alone share a scene together, but my first day, which was Patrick's last day on the set, just to get that handover, which I never had in the previous movie, it really felt like a kind of relay and that energy being passed," McAvoy told GMA. "The custodian of this wise, empathetic, caring, priestly character, at times, being handed over to this reprobate with long hair dressed in '70s gear with a psychedelic shirt. It felt like, 'Shouldn't we do something? This character will not be safe with me.' But it was nice."
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But there were some times offscreen when the actors didn't get along so swimmingly.
"I have never felt older in my life than being in the trailer park, which we call the base camp, with these guys, because they were running around with BB guns, shooting at each other," Jackman said. "I was this far from going, 'You youngsters, stop that! This is very unprofessional.' I felt like the old guy, locking myself in my trailer: 'Please don't come and get me. Don't shoot me. I don't want to be shot.' "
McAvoy then revealed that the BB gun fight was even more bizarre because while Jackman was in his trailer, he was doing vocal warm-ups to Les Miserables.
X-Men: Days of Future Past hits theaters May 23.
Watch GMA's full interview with the cast below.