The two stars reportedly fell out while filming Fast 8 and Johnson stunned fans when he appeared to take aim at his castmate in a social media rant about his male co-stars' bad behaviour behind the camera, calling them "candy a**es".

He has never named names, but insiders claimed the post was targeted at Diesel, who is also one of the film's producers.

Johnson, who used to wrestle as The Rock, fuelled the speculation earlier this month (Aug16) when he took to Instagram to thank the cast and crew as the movie wrapped. He did not mention Diesel.

"Finished strong and on to the next. That's an officially (sic) wrap on #FastandFurious8," Johnson wrote below a shot of himself posing by the open door of a private jet. "Thank you to our director @fgarygray (F. Gary Gray) for the vision and execution. Thank you UNIVERSAL for being tremendous partners as always, thank you to all my fellow co-stars for the daily effort and grind.

"Scott Eastwood you handsome sumb**ch (sic)! Natalie Emmanuel I have a cold Budweiser ready for you and Tyrese Gibson you still have the biggest smile and forehead I've ever seen."

He added, "And a huge THANK YOU to our hard working production crew - the backbone of our business. Your kind words meant a lot to me last night - thank you! In the end, we all rallied, as great teams do, kicked a** and will deliver an amazing movie to the world. Proud of our entire FAST FAMILY."

Eastwood explains he grew very close to his castmates while they were shooting and never noticed any friction between Vin and Dwayne.

"I had a great time working on the film," he told Entertainment Tonight on Monday (29Aug16). "I don't know anything about that stuff."

"We had barbecues, like, every day on set," he continued. "Tyrese would put on barbecues for everybody. We'd go run out and shoot a scene and come back and listen to music and eat grilled chicken."

Meanwhile, it seems the so-far one-sided war of words is all a ruse for an upcoming WWE showdown between Johnson, who reprises his role as government agent Luke Hobbs for the fourth time in the upcoming action movie, and Diesel, who has appeared in all but one of the Fast & Furious films.

"They are playing a huge prank, and it's all for publicity," a source told Life & Style magazine last week. "The Rock convinced Vin to amp up the drama between them so they could turn it into a WWE match to help promote the April, 2017 release of Fast 8."