Sean Penn was chillaxed on The Late Show Monday night. The 57-year-old Penn admitted he was sedated. “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 said. Penn then lit up a smoke. Penn also revealed that he is not as interested in acting, and has moved on to novel-writing. He plugged Bob Honey Who Just Do Stuff: A Novel on the show as well.