De Schotse acteur James McAvoy vertolkt in X-Men: Days of Future Past voor de tweede keer de rol van Professor Charles Xavier, het personage die in de eerste X-Men trilogie nog gespeeld werd door Patrick Stewart. Ook hij zal een rol hebben in de zevende X-Men film. In de laatste editie van Total Film besprak McAvoy de eerstvolgende X-Men film na The Wolverine, die volgend jaar zomer verschijnt.

“I thought the biggest thing that X-Men: First Class (2011) gave the franchise was a real palpable sense of humor that wasn’t just for a couple of moments. It was running through the thing. And I hope that continues. I don’t know how easy it will be for me to be a part of that as my character’s going to be in a pretty [frick]ed up place. It’s a shame because I like the fact that Charles Xavier was witty and funny and a bit of a lecherous old guy trapped in a 30-year-old’s body.”

Ondanks dat McAvoy niet veel prijs wil geven over de verhaallijn van Days of Future Past gaat hij wel in op de reden waarom zijn personage Xavier kaal wordt: “[screenwriter] Simon Kinberg and I had a chat about it and we came up with a whole bunch of idea about how, why and where he might go bald. It’s got to be linked to the plot though. In the comics, he lost his hair as soon as his powers awakened, and we clearly didn’t follow the source material. It can’t just be that he looks in the mirror at the end of the film and goes ‘Oh [frick], I’m losing my hair’. Although that could be quite funny with all this shit going on... he goes ‘Arge, I’m really stressed...’”