Credit: Michael Rozman/Warner Bros.; George Pimentel/

Who knew Justin Bieber was such a Friends fan?

Matthew Perry is in on the 16-year-old singer's surprising little secret.

"I found out that [Justin], when he checks into a hotel, we all use fake names," the actor (whose Mr. Sunshine debuts on ABC this week) said on Tuesday's Ellen DeGeneres Show. "He uses 'Chandler Bing'," revealed Perry, name-checking his famous TV character.

"Well, now people know," DeGeneres cracked.

"Yeah," Perry retorted. "Gotta find a new one, pal!"

The TV vet wouldn't reveal what his own fake check-in name is -- but it sure isn't Justin Bieber. "Yeah, I would never. That's the worst name I could use!"