The source told Life & Style magazine that Johnson and Diesel will settle their (fake) differences in the ring at WrestleMania 33, which takes place two weeks before Fast 8 is released next year.
"They are playing a huge prank, and it's all for publicity," the insider said.
Johnson later addressed the feud again on Instagram, writing: "Like with any team - that's a family - there's gonna be conflict. Family is gonna have differences of opinion and fundamental core beliefs."
"To me, conflict can be a good thing, when it's followed by great resolution. I was raised on healthy conflict and welcome it. And like any family, we get better from it."