Chaos: Jennifer Lawrence on Letterman

When JLaw comes to town, things get crazy!

That's what happened Wednesday night when Hunger Games star Jennifer Lawrence visited David Letterman's show.

She talked about "hating" singing. But then she growled one out.

They also talked about colonics, ulcers and how she just can't relax. "I took some time off. I lost my mind. I don't know how to explain how crazy I went," she said.

Letterman admitted he's a "little worried" about retirement.

"Don't do it!" she said. "Just keep doing this until you die!"

Said Letterman: "I'm sitting at home a couple of weeks ago on a Tuesday and the next thing you know I'm watching Ellen."

She was there to show a clip of the movie, but after getting sidetracked in a confusing chat about bowling and about introducing the movie, JLaw said, "You wanna get out of here?" and out they walked.

Then, after the show, Lawrence was apparently mobbed by overzealous fans as she stopped to sign autographs, reports the The Daily Mail. The star had to be ushered quickly to her waiting car by security guards.