Sean Penn Lit up a Cigarette on the ‘Late Show’ While Riding the ‘Ambien Train’ (Video)

And host Stephen Colbert was ready with an ashtray

Note to all late-night hosts: If you have Sean Penn booked on your show, you should take a cue from Stephen Colbert and have an ashtray at the ready.

The actor stopped by “The Late Show” on Monday to promote his new book, and he warned Colbert he was still a bit dazed after taking an Ambien following his red-eye flight the night before. So, naturally, he decided to smoke his way through the 10-minute sitdown.

He worked pretty hard to stay focused throughout the interview, and chat about his novel “Bob Honey Who Just Do Stuff,” which he describes as “the conversation once a year with the drunken uncle.”

When the topic of Netflix — the home of Penn’s ex-wife Robin Wright’s series “House of Cards” — came up, Penn cryptically said they would probably be “paying off settlements for years.” But he chose not to expand further on that front when Colbert looked confused. (And neither dared touched on the Kevin Spacey ousting.)

Toward the end of this interview, Colbert said he’d really prefer if Penn quit smoking, since he wants him to be around for a long time. The actor noted his habit ensured “job security for oncologists.” Well he’s not wrong there.

Watch the clip above.