Earlier this week, we reported that a scene from 20th Century Fox's X-Men: Days of Future Past will be attached as an end credits scene in The Amazing Spider-Man 2, which got many fans excited for possible Marvel crossovers between Sony, 20th Century Fox and even Marvel Studios. It was later revealed that director Marc Webb is still under contract at 20th Century Fox, and the studio would only let him make the sequel if Sony promoted X-Men: Days of Future Past for free.

When asked about the possibility of Sony joining forces with Marvel Studios and 20th Century Fox, The Amazing Spider-Man 2 producer Avi Arad revealed that a cross-over will only happen when the studios have run out of other ideas, although that likely won't happen anytime soon.

"I think I'm probably a little bit of the militant here. I think it will take a moment in which we've run out of ideas. There's so much to tell about Spider-Man. There's so much to tell about The Sinister Six. The relationship between Spider-Man and Venom will bring a whole other world in. We did it in the books; we did team-ups all the time. Even with DC. You know, we'd flip a coin, 'Okay, who's going to win, Batman or The Hulk? We'll make a cover out of it.' But we really feel very confident that we have so much to do [...] Peter Parker is unique; he's really different. He's not an Avenger. He's not an X-Man. He's unique and we revere that. And we'd rather work really hard to have the right ideas than - you know in the toy business we used to make toys glow in the dark when they weren't selling well and it gave at least another Christmas. We don't need it yet."

With The Amazing Spider-Man 3 and The Amazing Spider-Man 4 already in development, along with The Sinister Six and Venom spin-offs, it doesn't seem that these producers will be running out of ideas anytime soon.

Producer Matthew Tolmach also chimed in about crossing over with other Marvel comic book properties, which he believes would be nothing more than a stunt.

"You know Avi always refers to that question as a stunt. If you were to do that, you know, Spider-Man in the Avengers is a stunt. And I get why everybody - you know, fans and audience members and movie goers - I understand it. When you think about The Sinister Six and you think about Venom and you think about Carnage and you think Spider-Man in whatever way you want in association with those movies, they feel like they're built for Spider-Man. Like that's where his story needs to go and wants to go and it has to be about more than a stunt. Stunts can be cool but it's also a business, and so the other side of the answer is they're owned by different companies. And there's a ton left in Sony's world. There's a lot of business left because there's a lot of story left. So for them to want to take this character and put it with Marvel and Disney is a huge undertaking and probably, as Avi's saying, isn't necessary until you feel like, 'Wow, we're sort of out of ideas. What should we do?' And we're far from out of ideas."

If you're hoping that Andrew Garfield's Spider-Man one day joins The Avengers in their cinematic universe, it seems like a longshot that it will actually happen on the big screen.