Jennifer Lawrence stripped naked in front of Zoe Kravitz one of the first times they hung out together.

The "X Men: First Class" co-stars hit it off after making the movie together but Kravitz admitted she was surprised that Lawrence, 21, was so comfortable around her so soon after they met.

Kravitz -- whose father Lenny Kravitz stars with Lawrence in "The Hunger Games" -- told "Rolling Stone" magazine: "I'd met her a few times, and she was like, 'You should come over and we'll hang out.' So I go over to her apartment, and she opens the door in a towel. She's like, 'Come in, sorry, you're early, I was about to shower.' And she drops her towel and gets in the shower, and starts shaving her legs, totally naked. She was like, 'Are we here yet? Is this OK?' And I was like, 'I guess we're there!'"

Woody Harrelson -- who also stars in the movie set in a futuristic north America in which teenagers are forced to fight to the death for entertainment -- revealed Lawrence was equally forward when they first met.

He explained: "I was on my bus, and on my bus I have a yoga swing. Jennifer comes on, and she goes, 'Hi, Woody, I'm J... is that a sex swing?' Her first sentence to me."

Meanwhile, Josh Hutcherson -- who plays Jennifer's love interest Peeta Mellark in the movie -- said he was treated to a "45-minute rant about zombies and the apocalypse" when they first spoke.

He said: "When I got cast, she called me up for one of those five-minute 'Excited to work with you, blah, blah, blah' things. The conversation started with her saying, 'Think about a catheter going in - ouch!' and then turns into a 45-minute rant about zombies and the apocalypse."