Sean Penn lights up cigarettes on ‘The Late Show with Stephen Colbert’

Sean Penn made a smoky appearance on The Late Show with Stephen Colbert to promote his book.

The actor told Colbert Monday that he had taken a sedative “to get sleep after a red-eye flight” and he went on to light a cigarette.

“How do you tell Sean-Penn-on-Ambien from Sean-Penn-NOT-on-Ambien?” Colbert asked.

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The 57-year-old actor discussed why he no longer finds joy in acting.

“The greatest thing that an actor can bring to the party is to play well with others — it’s the collaboration — and I increasingly don’t play well with others,” he explained between puffs of his cigarette. “And so it becomes less enjoyable, because I love that process when I love it, but I’m not loving it anymore and that’s really why I finally came around to writing a novel because I didn’t have collaborators. I was never disappointed with me.”

The two-time Academy Award winner described his book, 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. Penn said that it was “job security for oncologists.”

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Some viewers were confused by what they were witnessing on The Late Show.

Watch Penn on The Late Show in the video above.

The Late Show with Stephen Colbert airs weeknights at 11:35 PM on Global.

—With files from the Associated Press