WATCH: A sedated Sean Penn lights up and smokes a cigarette during his live interview with Stephen Colbert


New York — Sean Penn made a smokey appearance on The Late Show with Stephen Colbert to promote his book.

The actor told the host on Monday he had taken a sedative "to get to sleep after a red-eye flight" and then lit a cigarette.

The two-time Academy Award winner described his novel, Bob Honey Who Just Do Stuff, as "the conversation once a year with the drunken uncle."

Penn lit a second cigarette and Colbert asked him to consider quitting but the 57-year-old replied, saying it was "job security for oncologists."

WATCH CLIPS OF THE INTERVIEW HERE: