When asked in an interview with Yahoo! Movies what he thought the odds were of The Avengers mashing up with X-Men, Hugh Jackman had this to say:
You know, I think as an optimist I would love it. ... You’re in a very complex world where big, big sums of money are being spent for different franchises and so getting them together is difficult. Two years ago I would have said you’d be a real optimist to think it would ever happen, but weirdly I just think it maybe could. I think there is a possibility that it will happen.
When asked specifically which Avenger he would like to see make an appearance in X-Men, the Wolverine actor went straight for Iron Man. He elaborated on the topic, making it clear that his excitement surrounding the potential mashup has a lot to do with Robert Downey Jr., calling him and his Iron Man persona "inseparable."
This isn't the first time Jackman talked about about the possibility of these two characters crossing paths. In an interview back in 2014, he said he'd love to "mix it up with Downey Jr. and Iron Man and kick his ass." More recently, in an interview just after the Marvel/Sony deal he showed the same enthusiasm at the prospect of Spider-Man joining The Avengers and again tossed in the idea of Wolverine and Iron Man sharing the screen.
So the big question is whether Fox would be willing to work out a deal with Marvel, similar to that of the latter's recent agreement with Sony. With the success of Bryan Singer's 2014 installment Days of Future Past, it's highly unlikely Fox would need to rush out and strike such a deal. They'll at least want to see the results of their upcoming X-Men: Apocalypse (slated for release in 2016) prior to calling that shot.
While the very idea of The Avengers meeting up with X-Men on the same screen is unbelievably exciting, there's something to be said for the latter's isolation in the comic universe. And although the possibility of seeing Iron Man duke it out with Wolverine is mind-blowing to say the least, it likely won't happen for several years, at which point Jackman (who jokes he may play Wolverine all the way until he dies) may have long since been replaced.