The "Trainwreck" star plays Jakob, the brother of Diesel's movie character Dominic Toretto in "F9: The Fast Saga" and, since it's the first time the sibling has appeared in the action film series, Vin was determined to pick the perfect person.
"OK, so obviously I'm multicultural," the franchise producer quips to pop star Kelly Clarkson on her U.S. daytime talk show. "You could have cast anybody to be my brother. Anybody, right? You could have cast anybody in the world to be my brother and it would be OK."
"For two months before I went to (start) filming I created a shrine, where I could do all the combat training, all the stunts, and I had the Charger (car) there to simulate the garage, to get into the Dom state of mind."
But while his personal preparation for F9 went according to plan, Vin was suffering "anxiety" over who should play the critical role.
"The idea of the brother worked great on paper," he continues, "but once the time came to cast it - anxiety. Who could you cast to be Dom's brother? Twenty years into the game and the audience knows our mythology so much, who could you cast?"
Then the action man felt a powerful sensation when he pitched up at the shrine for another day of pre-film training.
"I had this strange feeling, and if you look back on my Instagram you'll see the post, because I thanked Pablo (Walker)," he says.
"Because I had the strange feeling that Paul Walker had sent him (Cena)."
And now "F9" is already roaring to box office success in territories like China, South Korea, Russia, Saudi Arabia, and the United Arab Emirates, where it hit the starting grid last month (May21), Vin will never forget what he's sure was a special signal from his much missed friend.
"Very magical," he adds with a smile.