Vin Diesel "went through three boxes of tissues" after Paul Walker's death.
The 47-year-old Hollywood star, who appeared alongside Walker in the 'Fast and Furious' franchise, admits he couldn't control his emotions on set following the death of his close friend, who died in a car accident in November 2013.
He told Variety magazine: "I'm supposed to be in killer mode. I went through three boxes of tissues, and I felt so embarrassed.
"I had always been the kind of actor that other actors respect. I was just failing so hard. My nose was running and my eyes were tearing. I had to walk off set and try to get all the fluids out. I couldn't contain my emotion ... It became the toughest film I ever had to shoot."
Meanwhile, Vin announced earlier this week that he and his girlfriend Paloma Jiminez had named their new baby girl Pauline in honour of his friend.
He explained: "I named her Pauline. There's no other person that I'm thinking about as I'm cutting this umbilical cord.
"I knew he was there and I felt like, you know, a way to keep his memory a part of my memory, a part of my world."