Thursday night on "Conan," host Conan O'Brien discussed pop idol Justin Bieber's Twitter apology to former President Bill Clinton and revealed some lesser-known apologies made by the pint-sized superstar to other big name celebrities.

Canadian singer Justin Bieber made headlines this week when video emerged of him urinating into a mop bucket in a restaurant kitchen in New York City, then spraying cleaning fluid on to a photo of Bill Clinton.

"Fuck Bill Clinton!" he said before he and his droopy pants-wearing entourage left the scene.

The next day, Bieber posted on Twitter that he had spoken to the former president and apologized.

O'Brien said that what many people don't realize that Bieber has been posting Twitter messages to other famous people. To Pope Francis, he wrote, "@pontifex Dig your costumes. Nailing my look was 1st step for me. You're on the path. #keepstriving."

To Paul McCartney, he tweeted, "Who r u?"

To Stephen Hawking, "Thanks for being cool about my posse taking your wheels for a joyride. U the chillest sick kid I ever met!"

And to Morgan Freeman, "Get well soon, sir. South Africa needz u!"

Watch the video, embedded below via Team Coco: