The premise has compelling elements to it, Singer said. "Just doing younger mutants is not enough. The story needs to be more than that. I love the relationship between Magneto and Xavier, these two men who have diametrically opposite points of view but still manage to be friends -- to a point. They are the ultimate frenemies."
Singer turned to Shuler Donner and said of "X-Men 4": "Hold that one off for just a little, I'm fixated on the other one right now." She nodded and answered, "I will, I will ... I'm holding it open with high hopes. It's totally different [from 'First Class'] and it will be so interesting for you."