Including a scene that took a whole week to film, and a celebrity cameo that happened by pure chance.
The Oscar winner also juggled acting and producing while recovering from serious injuries she sustained on the first day on filming.
The Titanic star's Lee Miller biopic was given its first outing at Toronto International Film Festival but critics can't agree on whether it's good or not.
The Oscar-winning Titanic star was a surprise addition to the festival's line-up on Sunday.
“We did this together, kiddo,” the I Am Ruth star said, as she picked up the award for Best Actress.
“When I lost touch with Kate, it was more heartbreaking than some breakups that I’ve had."