What would it take for Robert Downey Jr. to suit up for a fourth Iron Man film? For Marvel to hire Mel Gibson to direct.

OK, the 49-year-old actor is probably joking, but it's difficult to tell in this new Deadline interview, which covers his storied career, his new film The Judge and, yes, his future as Tony Stark.

"That’s all being talked about on a bunch of different levels right now," Downey tells the website. "To me, it comes down to what’s the half-life of people enjoying a character? It’s different on TV, where you expect the longevity over seasons while movies get a two- or three-year break. Marvel keeps stepping up its game, and I appreciate the way Kevin Feige and all the creatives there think. They are as in the creative wheelhouse as any great studio has been at any point. So it becomes a matter of, at what point do I cease to be an asset to what they’re doing, and at what point do I feel I am spending so much time either shooting or promoting these films that I’m not actually able to get off the beachhead and do the kind of other stuff that is good for all of us. Each one of those movies is spread over two years and some people fit other things in.

"But I’m not 42, I’m turning 50," he continues, "and now I’ll have two small kids instead of one grown one, and eight Team Downey projects with people who are imagining I’m not just spending Warner Bros’ money out of vanity, but that I’m taking it seriously. It all has become this thing that has to be figured out. It has come to a head, right now, where the points of departure will be."

While Downey's ruminations about his age aren't new -- his injuring on the set of Iron Man 3 seems to have been a turning point for him -- his acknowledgement that a fourth solo film is being talked about would seem to be. It was just early last month that the actor said there was no plan for Iron Man 4; of course, talks don't necessarily equal plans.

After much speculation and hand-wringing, Downey, the highest-paid actor in Hollywood, signed a deal in June 2013 to return for Avengers: Age of Ultron and its sequel. Through box-office bonuses and back-end compensation, he earned more than $50 million from The Avengers alone.

Now how about that Iron Man directing gig for his old friend Gibson? "Why not?" Downey tells Deadline. "That movie would be bananas."