While Robert Downey Jr. and Gwyneth Paltrow can't play Tony Stark and Pepper Potts forever, who are the actors that can replace them? And could it happen after the next Iron Man movie?

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While there aren't any immediate rumors that say Downey Jr. and Paltrow are done, it would seem after doing five movies with a sixth and seventh on the way, the two may look at moving on from the Iron Man franchise. Over at MoviePilot, they looked at a few couples who could take over as the famed duo.

The first choice was Colin Farrell and Olga Kurylenko. "He is most fans' number one choice to take over as Tony Stark for Iron Man 4. About 10 years younger than Robert Downey Jr, he could well be the man to guide Iron Man through the next Phase of the Marvel Universe," the site said.

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"Olga Kurylenko, meanwhile, was considered for Wonder Woman and appeared in the 2008 James Bond movie Quantum of Solace, proving that she can hold her own when paired up against a leading man. She is also 34 years old, making her a good fit for Farrell."

Their second choice was even younger with James Franco and Emma Stone taking over. "James Franco certainly shares some of the qualities of Tony Stark; both men are arrogant, rich, self-proclaimed geniuses," the site read.

"Emma Stone, meanwhile, was extremely popular as Gwen Stacy in The Amazing Spider-Man franchise. In that movie, she had the exact combination of teasing, tolerance and affection for her superhero partner that makes the Iron Man / Pepper Potts relationship so enduring."

Their final choice was a Hollywood couple, Ryan Gosling and Eva Mendes. "Ryan Gosling's most celebrated performance to date was in 2011's Drive, where he played a sympathetic seeming stunt driver with a violent streak. Given that Tony Stark and Iron Man may be set for more antagonistic roles in upcoming Marvel story lines (such as The Avengers Civil War) Gosling could be the right man for the job," the site said.