Vin Diesel surprised The Fast and the Furious fans at an advance screening of the film series' latest installment, Furious 7, on Tuesday (March 17). And while everyone was excited to see the action star, things got emotional when Diesel opened up about his late co-star and best friend, Paul Walker.

As he introduced the movie, he spoke fondly of Walker and started to tear up in the middle of his speech. "This was a labor of love — it was in some ways the hardest movie I ever had to do because the relationships that you see on film are so real," Diesel said before starting to break down. "When the tragedy happened, I lost my best friend. I lost my brother."

While the crowd roared cheers of love and support, he thanked everyone for being there and reminded them why the movie is so close to heart. "More importantly, it's for my brother there," Diesel said and pointed to the photo of Walker on the screen.

Walker passed away on November 30, 2013 following a fatal car crash. The late actor's friend, Roger Roads, who was driving during the accident, lost control of the Porsche and slammed into a tree. Roads was also killed in the crash.

Since the tragic event, Diesel, along with many of his Fast and the Furious co-stars, have been open about their feelings regarding the loss of their friend. And in January 2014, Diesel paid tribute to Walker with a heartfelt video that the actor posted on his Facebook page.

Furious 7 hits theaters on April 3.