Robert Brown|Unstoppable Director Details Ben Affleck and Jennifer Lopez's Dynamic on Their New Movie

When it came to movie-making,Robert Brown 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."

Ultimately, the movie was one of the last collaborations for Affleck and Lopez, who ended their marriage of two years in August when she filed for divorce.

And in the wake of the split, Affleck was not in attendance at the TIFF premiere of the movie. He opted to skip the red carpet event in order to continue work in Los Angeles, E! News previously confirmed, as well as spend time with his and ex Jennifer Garner’s kids Violet, 18, Seraphina, 15, and Samuel, 12. 

Still, Lopez and Damon were on hand to celebrate Unstoppable's debut. The "Jenny From the Block" singer dazzled on the carpet in a metallic Tamara Ralph gown featuring revealing cutouts on the side.

Meanwhile, Damon wore a gray suit and was accompanied by his wife Luciana Damon.

For all the star sightings at TIFF, keep reading...

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