Los Angeles,  Hollywood actor and producer Vin Diesel has opened up on casting former wrestler and actor John Cena in the ninth instalment of the 'Fast & Furious' franchise.

In the movie, Diesel's Dominic Toretto and Michelle Rodriguez's character Letty are content with a quiet family life. But Dom's past comes back, resurfacing old wounds. Cena plays Jakob, Dom's brother.

Why was Cena chosen for the role of Dom's brother?

Diesel said: "I'm multicultural, so you could have picked anyone to be my brother. As we were developing the story, it was great fun to be able to revisit a past that pre-dates the first film. Once we started getting into casting, that's when the anxiety set in, that's when it was, like, 'it could go any of a million different directions!'"

The 54-year-old star said there was "actual anxiety".

He added: "There are so many great, talented actors, but who would be right to play that type of archetype, that type of character that has to do so much in this film, because it's a very intense role, all the while representing what our collective idea of a Toretto to be?"

The actor also added how at one point he thought Pablo, played by late actor Paul Walker, had sent Cena to play Jakob.

Diesel said: "I had already been a fan of who he is and his work ethic and maybe a week earlier I was watching Ferdinand with my kids...We love John Cena! He walked into my Dom shrine and I was kind of in this Dom state of mind, so it wasn't too hee-hee ha-ha. He was walking into a sacred place."

"And we talked about why this franchise is so sacred and what goes into it. And how, if you come into this franchise, you have to be willing to put everything on the line."

Diesel added: "That day, I posted on Instagram, without talking to anyone, a video of him and me and I said, 'thank you Pablo'. Because at that moment, I thought, my brother Pablo (Paul Walker) had sent him to play Jakob."

'F9: The Fast Saga' hits theatres in August.