The 40-year-old actress, who usually stays mum on her longtime boyfriend and hasn't been spotted with him in public for almost five months, is opening up to E! News about her upcoming film How to Catch a Monster, which Gosling wrote and directed.
"It's basically a dark fairy tale, and I play a woman named Cat," Mendes told our own Catt Sadler exclusively at her NY & Co. pop-up shop event at the Beverly Center in L.A.
"Yeah, it's a beautiful, beautiful film," she added.
How to Catch a Monster, which also stars Christina Hendricks and Saoirse Ronan, is Gosling's directorial debut. "He really created the most beautiful, collaborative, creative atmosphere on set," Mendes said, adding with a smile, "I know I'm biased."
"He's the best," she gushed. "He's the best."
So does Gosling run a tight ship while working behind the camera? Watch the video for Mendes' answer!
For more coverage of Mendes' event, tune into E! News tonight at 7 p.m. & 11:30 p.m.