Because shared superhero universes are making billions of dollars, thanks to Marvel Studios and Warner Bros., it’s not surprising that Fox would also make a play to join in the fun. The studio owns the movie rights to the very successful X-Men franchise, as well as the soon-to-be-revived Fantastic Four franchise, and since every studio these days is obsessed with connectivity, rumors have swirled for months that Fox will bring the two together in some kind of crossover film.

Fox hasn’t really said much about how likely such a project is, but this week, director Bryan Singer (X2, X-Men: Days of Future Past) was kind enough to talk about it with Yahoo! Movies. In a video interview to promote the Days of Future Past “Rogue Cut,” Singer confirmed that there are “ideas in play” for a crossover movie, though he did not confirm that those ideas would actually come to fruition, noting that development would depend on the success of the upcoming X-Men: Apocalypse and Fantastic Four films.

“I think to just say you’re going to do it is kind of a mistake. I think you have to really see how the films evolve before you make that decision to completely commit to that, but there are those ideas in play.”

So, we’ve got our best evidence yet that these two superhero franchises will cross over. Watch out, Marvel.