"Michael knew that he would be, well, not sharing the frame with Ian McKellen, but sharing the movie with Ian McKellen," explains Singer, "so where on First Class he tried to be as different as possible from McKellen, because that was a very different character, he now knows as an actor he'd have to bring his performance slightly closer to Ian's because he's heading in that direction."

"There's a line in the movie, 'He's always had a way with guns'," reveals Singer. "That's how he crippled Xavier, and he's such a powerful mutant but in this particular moment he's holding a gun and I like that. He's a product of the Second World War and he knows how to use a gun as much as he does his powers."