Kourtney: Scott Is Working on Not Being a "Punk"

On Wednesday's Late Show With David Letterman, the late night host grills Kourtney Kardashian about her boyfriend (and father of 5-month-old son Mason), Scott Disick.

"Who's the guy who's always drunk and mouthing off?" he asks in the video, above. "That's my boyfriend," says Kourtney, 31 (who was promoting the new season of E!'s Kourtney and Khloe Take Miami with sister Khloe). "He got a little crazy in Miami."

Kourtney says it wasn't a good idea to have Scott, 27, and Khloe, 25, living under the same roof while shooting the show.

"Things got a little intense," she tells Letterman.

"He seems like he might have a little punk in him," Letterman quips.

"He has been working on that problem," replies Kourtney.