Vin Diesel has revealed that he found it difficult going back to work after the death of Paul Walker.
Walker was killed in a car accident in November, in the middle of shooting the latest instalment of the Fast & Furious franchise.
While filming on that film was halted, Diesel had to work on Guardians of the Galaxy: he is lending his voice to the character of Groot.
While the actor found it challenging he revealed that focusing on that project was a huge help.
During a Facebook Q&A, the actor said: "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."
Guardians of the Galaxy will hit the big screen this summer, and is the latest superhero offering from Marvel.
The movie sees Diesel team up with Chris Pratt, Zoe Saldana, Bradley Cooper and Dave Bautista: James Gunn is in the director's chair.
Filming has resumed on Fast & Furious 7, with Diesel reprising the role of Dominic Toretto.
Guardians of the Galaxy is released 31st July
Fast & Furious 7 is released 10th April 2015.
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