"The Fast and the Furious" franchise lost one of their own when Paul Walker tragically passed away in November. Co-star and close friend Vin Diesel reveals that his role in "Guardians of the Galaxy" helped him cope with the loss and get back to work.

"It was very personal -- it was the month after the accident happened with my brother Paul Walker and it was the first time I had worked since," he told a fan.

"Although it was challenging, just to get back to work was therapeutic - especially as Groot. There was an innocence about the character that was just refreshing - and it may have been more challenging under other circumstances, but at that time, it was very therapeutic."

Diesel plays voice over to the talking monster tree, who can only say, "I am Groot."

He also explained how much fun the cast had making the movie and saying that line.

"James Gunn and I were having so much fun with it. So it could have been a thousand. And it was amazing to go in there and work with someone who wanted to explore the character - we wanted to teach 'I am Groot' to mean something different - It reminded me, as an actor, how much we can do with so little - and if we're passionate about it, good thing can come from it."

He then added, "Chris Pratt is hysterical. He is just refreshingly hysterical."

Walker died suddenly with friend Roger Rodas after they crashed their Porsche in Valencia, Calif. in the middle of filming the next "Fast" film. The cast has since resumed production, with his brothers finishing out his roles. How perfect!