The A-list cast of the newest Disney/Marvel movie "Guardians of the Galaxy" is about to take flight in less than a week. For one of its stars, Vin Diesel, doing the film was perhaps a cathartic experience.

Diesel, star of the "The Fast and the Furious" films, lost his good friend Paul Walker last November to a fatal car crash. Diesel claimed that doing "Guardians of the Galaxy" helped him to cope with the loss of his friend.

A week ago, speaking at a press conference for the promotion of "Guardians of the Galaxy," Diesel opened up by saying that connecting with his character Groot, the tree creature, was really emotional, and that it helped him to deal with people again.

"For me, it was at a very important time that I did this. Because it was in December. It was the first time I was coming around humans again," Diesel said, MoviePilot reported.

At that time, Diesel says he just resumed working again.

"There was something very therapeutic about, in my personal life, but I guess in my professional life, too, dealing with death, and then playing a character that celebrates life in the way that Groot celebrates life," he said.

Diesel's Groot in the film, is a walking, talking tree, who says very little than "I am Groot." While Groot might say very little, the character emotes feelings, and has charisma, Newsarama reported. Diesel was not alone in Groot's process. The film's director and co-writer James Gunn gave Diesel copious notes about his character.

"I don't think anyone's ever seen my script, but man ... you should see my script," Diesel said. "The left side might just say 'I am Groot,' but the right side would have a whole paragraph on what 'I am Groot' meant in that situation."

The process of understanding Groot for Diesel was perhaps less challenging than understanding Walker's death. Diesel and the rest of the "The Fast and the Furious" cast were in shock at the sudden loss. After Walker's death in November last year, production on "Fast & Furious 7" had to be shut down, and all kinds of new arrangements had to be made including rewriting the script, and hiring Walker's two brothers Cody and Caleb to complete some of Walker's unfinished scenes, Yahoo! Movies reported.

Diesel and the cast, Michelle Rodriguez, Tyrese Gibson and Ludacris, just to name a few, received a short break from production to mourn the loss of Walker. The cast  via social media, and especially the Walker family, have expressed their shock and sadness over the loss of their friend, brother, son and father, Yahoo! Movies reported.

"Guardians of the Galaxy" came at a healing time for Diesel. The film centers around Star-Lord, played by Chris Pratt ("Parks and Recreation," "The Lego Movie"), who gets arrested and is thrown together with Drax the Destroyer, played by Dave Bautista ("World Wrestling Entertainment"), Gamora, played by Zoe Saldana ("Star Trek," "Rosemary's Baby"); Rocket Raccoon, voiced by Bradley Cooper ("The Hangover," "Silver Linings Playbook"); and Groot.

These five characters are chosen to be the Guardians, and they must fight in an intergalactic conflict with Ronan the Accuser, played by Lee Pace ("Pushing Daisies," "The Hobbit" films). While, all the time there is an intergalactic bandit, Yondu, played by Michael Rooker ("The Walking Dead," "Jumper"), who is waiting to take sides.

"I took my kids to the screening to see this movie, and ... something very beautiful happened in playing this role. Something that, as an actor, I never would have imagined. And that is that when my kids see trees, they refer to them as my brothers and sisters. The idea of being associated with trees like that, is remarkable, it's so much more gratifying than you ever could imagine," Diesel said.

"Guardians of the Galaxy" comes to theaters on Aug. 1.