Why Paul Walker's mum apologised to Vin Diesel after his death

Paul Walker and Vin Diesel were best friends. Photo / Getty

Vin Diesel has opened up for the first time about the heartbreaking conversation he had with Paul Walker's mother the day after the actor died in a fiery car crash.

Diesel, who's in the midst of the press tour for the eighth Fast and the Furious movie, revealed he went to see Cheryl Walker after the fatal accident in 2013 - and surprisingly, she apologised to him.

"And I said, 'Why?'" Diesel told SiriusXM Entertainment. "Why are you apologising to me? And she says to me, 'Because you lost your other half.'"

While the actor has been very open about his struggle with grief since losing his "brother" four years ago, he admitted it was that conversation which first made him realise the impact of the tragedy.

Paul Walker and Vin Diesel attend the world premiere of 'Fast And Furious 6' in 2013 in London, England. Photo / Getty

"She was telling me something that I wasn't even aware of," Diesel explained. "I wasn't aware of how profound the loss was."

The Fate of the Furious - out this week - is the first in the franchise without Walker.

"There wasn't a day, there wasn't a scene, there wasn't a second where I didn't have Paul with me in the making of this movie," Diesel says.

"It's not making the movie without Paul, it's, 'What's life like? What's living like without Paul?'"

The actors worked together on the Fast franchise for 13 years, after first meeting on set in 2001.

Following Walker's tragic death, Diesel even named his daughter Pauline in his honour.

"My mother only told me this a month ago, that his mother told my mum, 'Love your child. Just love your child'," Diesel revealed on the program.