With production on "Fast 8" currently underway, Diesel, 48, shared a touching account he had with one of the film's crew members with his social media followers.
"Many of the crew members who have worked on several of the past Fast films are here again to help us make something special," he captioned a throwback photo of himself seated beside Walker.
"One of them at the end of the week came up to me and said wow what we are capturing on film is excellent... And then looked at me and said Paul would be proud."
"Coming into shooting Fast 8, I knew that it was gonna be a darker road," he said.
"It's amazing how regardless of how successful you are, that you have to go into a dark place to channel a character - to feel a character.