Fast and Furious 7 opened strong at the box office, while the crew opened up about their grieving fellow cast member, Paul Walker.

During an interview, star Vin Diesel shared his personal feelings and deep-felt loss for his friend. Although admitting he does not like to sing in front of people because he is not good at it, he sang a tribute song to Walker.

He let out a few phrases from the song, “See You Again” from the movie’s soundtrack, dedicated to Paul Walker, according to Social News Daily.

After singing during the first part of the interview, Diesel fell into a toned-down, emotional state as he talked about how he felt going back to shooting the movie without his friend, and co-star, Walker.

“Oh my God, it was the hardest thing I had to do. I felt like it was almost unfair asking us to go back to work. When I act, I pull from the inside but when my inside is hurting or in pain – how do you do that?”

“I didn’t know a human could produce so many tears. I remember feeling self-conscious about it… If it wasn’t for the great team – that I call family – if it wasn’t for the obligation in honoring Paul… that is what drove us to the finish line.”

Fast and Furious 7 has been a huge box office hit. It broke opening weekend records upon release. What did not show was the difficulties the crew had in finishing the film without their co-star.

At this point, the franchise plans have come to a complete stop. Even with its success, there are no clear future plans. There has not been any talk of a writer or director taking on another installment of the series.