Jennifer Lawrence

Jennifer Lawrence explained the confusing photo of herself fully clothed and in bed with Kris Jenner posted earlier this week.

The Mockingjay Part 2 actress told a New York Times reporter Tuesday Jenner was part of a birthday surprise set up by her two best friends Aug. 15. Another part of the surprise was a very memorable cake.

"So I'm there, and people start singing Happy Birthday," Lawrence recalled. "Kris Jenner comes out holding my cake, which is a pile of [expletive], with a sign that says 'Happy Birthday You Pile of [expletive].' My knees buckled."

Lawrence, 25, said she fell on the floor, shocked by Jenner's presence. "It was the closest I've ever come to losing consciousness," she recounted. "I had no idea. I'd never met her before but we've always watched Keeping Up With the Kardashians. And then Kris Jenner and I sang 'Build Me Up Buttercup' on karaoke and took that picture."

Kris Jenner shared "that" photo over the weekend, prompting a startled, confused reaction from fans. "Happy Birthday you piece of [expletive]," Jenner wrote in the caption. "God I love you."