Sean Penn showed up to The Late Show a little more relaxed than usual.
During his guest appearance on Monday, the 57-year-old actor admitted he was still experiencing the effects of a sedative he took after a recent flight.
"You've inherited a little of the Ambien I had to take to get to sleep after a red-eye last night," the Mystic River star said.
"So, in other words, you're still a little bit on the Ambien train right now?" host Stephen Colbert asked him.
"A little bit," he replied.
Penn then proceeded to light up a cigarette right in the middle of the interview.
"I thought you might," Colbert said, whipping out an ashtray.
At one point, Colbert actually asked the actor to stop smoking.
"I wish you'd move on. Please don't smoke anymore," the late-night host said. "I don't mind. My parents smoked when I was a child, so it gives me happy memories to smell cigarette smoke. But we want you to be around for a long time and those things are bad for you."
"This is job security for oncologists," Penn replied.
The actor put out his cigarette; however, he had more than one during the interview.
In addition to discussing his smoking habits, Penn and Colbert discussed the two-time Oscar winner's decision to stray away from acting. Penn explained he didn't enjoy working with others as much as he used to.
"The greatest thing that an actor can bring to the party is to play well with others—it's the collaboration," he said. "And I increasingly don't play well with others. So, it becomes less enjoyable."
In fact, Penn has found a new creative outlet—writing novels. The Milk star promoted his new book Bob Honey Who Just Do Stuff: A Novel during the show.
Watch the videos to see the whole interview.