When it came to movie-making, Jennifer Lopez and Ben Affleck were an unstoppable force, according to William Goldenberg.

The Unstoppable director shared insight into the former couple’s dynamic during the filming of their sports drama, exclusively telling E! News’ Francesca Amiker that J.Lo and Affleck kept things professional throughout production.

“It’s always been about the movie,” Goldenberg said at Unstoppable‘s Toronto International Film Festival premiere Sept. 6, “and that’s their personal business. We just kept it about the movie. We just kept her eye on the prize.”

Starring Lopez and Jharrel Jerome, Unstoppable is based on the 2012 memoir of the same name by Anthony Robles, a champion wrestler who was born with one leg. Affleck and his longtime collaborator Matt Damon are both producers on the film.

And having previously worked with Affleck and Damon on Air, Goldenberg was very comfortable teaming up with the duo again. 

“They were so supportive and so behind me,” he shared. “They never overstepped or did anything to interfere and they were just there behind me. They were incredible. They’re professionals and they’re great storytellers.”