Tom Hiddleston had been bookies' favourite for a long time, and we can think of plenty of (sexy) reasons he'd be a good fit.
He's got previous experience playing a spy in the BBC drama The Night Manager, and that show's director Susanne Bier has been linked to the movie franchise too. Tom's costar Olivia Colman has also given him her vote. However, Tom's consistently played down rumours.