Justin Bieber Takes Over James Corden's Late Late Show Monologue: Watch the Video

Justin Bieber Takes Over James Corden's Late Late Show Monologue: Watch the Video

What Do You Mean . . . He's James Corden? Purpose hitmaker Justin Bieber made a surprise appearance at his buddy James Corden's Late Late Show on Thursday, Dec. 10, where he delivered the show host's monologue in his place.

"Hello, ladies and gentlemen!" Biebs, 21, said to the roaring CBS crowd as he launched into his opening monologue. "Welcome to the show. It's great to see you guys . . . Today, President Obama revealed that his favorite song of 2015 was 'How Much a Dollar Costs' by Kendrick Lamar."

At one point, the suited pop superstar was interrupted by a bathrobe-clad Corden, who came storming out from backstage. "Whoa, whoa, whoa," Corden, 37, yelled. "What is going on?! That's not me, that's Justin Bieber!"

"Sorry, man," Bieber replied, later adding: "What do you mean?"

The stars have previously collaborated. In May, Bieber joined Corden for an epic session of Carpool Karaoke. The clip was such a viral success that Bieber did a second take of Carpool Karaoke with Corden last month.

Watch Bieber's monologue above. 

Can't get enough of Us? Sign up now for the Us Weekly newsletter packed with the latest celeb news, hot pics, and more!