The filmmaker recently took to the stage with Turner at the Golden Globes when the movie scooped the 'Best Adapted Screenplay' prize. However, the pair appeared distant and Reitman has rarely acknowledged Turner during the film's promotional run.
Speaking to The Envelope, Reitman said that talk of a feud stemmed from the duo writing scripts for Up In The Air separately and then being handed joint credit by the WGA (Writers Guild of America).
"When our credits went up the first time and they say you're sharing credit with this other guy, you go, 'Who's Sheldon Turner?'" Reitman said. "But then I meet him and he's a great guy and beyond that we were actually drawn to this book for the same reason and we both sat down to write the same screenplay.
"Even though we never sat in the same room or shared a keyboard, we actually did write this movie together in a way, and because of that I'm very proud to share the credit with him."
Turner added that he and Reitman became friends after attending various awards ceremonies, saying: "Now that we've been sort of through this [awards] 'circuit,' which Jason is a lot more familiar with than I am, we've become friends. It's a unique situation."
Up In The Air, which stars George Clooney as a corporate downsizer obsessed with collecting 10 million frequent flyer miles, is in cinemas now.
> Click here to read our recent interview with Jason Reitman