The on-again/off-again feud between Fast & Furious co-stars Dwayne Johnson and Vin Diesel is well-documented. During the filming of The Fate of the Furious, Johnson took to social media to make some very ambiguous but weighty claims at an unnamed co-star, which was later confirmed to be Diesel.

For his part, Diesel didn't consider Johnson and himself having any beef, and declared that any rumors "may be blown out of proportion" in an interview last year. However, Johnson now reveals that their feud came down to professionalism, and he's not sure whether he'll return for Fast & Furious 9.

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"Vin and I had a few discussions, including an important face-to-face in my trailer," Johnson told Rolling Stone. "And what I came to realize is that we have a fundamental difference in philosophies on how we approach moviemaking and collaborating. It took me some time, but I'm grateful for that clarity. Whether we work together again or not."

As for Fast & Furious 9, Johnson is putting his time and energy into his Fast & Furious spinoff, Hobbs and Shaw, with Jason Statham. "I'm not quite sure," Johnson said regarding Fast & Furious 9. "Right now I'm concentrating on making the spinoff as good as it can be."

Johnson added, "But I wish [Diesel] all the best, and I harbor no ill will there, just because of the clarity we have." Before ending the interview, Johnson let out a smile and backtracked on his final statement. "Actually, you can erase that last part about 'no ill will.' We'll just keep it with the clarity."

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Universal has ordered two more films to conclude The Fast and Furious franchise. The ninth installment has a targeted release date of April 10, 2020.