"Saturday Night Live" alumni Bill Hader and Jay Pharoah just called out some musicians on their bad "SNL" behavior.

The topic came up on "Watch What Happens Live with Andy Cohen," because fans only ever want to know the juicy stuff -- your least favorite costars, the worst person who did this, etc. No one ever asks for positives.

In this case, that was bad news for Justin Bieber. Here's that part of the talk:

Caller: "Who was the worst behaved musical guest or host during your time at 'SNL'?"

Bill Hader: "Everybody wants to know worsts!"

Jay Pharoah: "We both know."

Bill: "It was Bieber."

Jay nodded.

Andy Cohen: "You talked on [Howard] Stern about that."

Bill: "Yeah, Bieber was -- he just was in a bad place. Maybe he's in a better place, but back then it was rough."

Jay: "I saw Kanye [West] yank somebody, that was pretty hilarious."

Bill: "Everyone's usually on great behavior. Everyone's very excited and great behavior, most time it's 100 percent. Yeah, Bieber's the only one in my experience. I think it was just, he seemed exhausted or at the end of a rope."

Justin Bieber, now 24, was musical guest in 2010 and both host and musical guest in February 2013.

During his 2013 talk on Howard Stern, Bill Hader had contrasted Justin Bieber's behavior with another SNL host, Justin Timberlake:

"Justin Bieber showed up with like 20 guys and every time, you know, when you're backstage it's very small constrictive place. And he had a guy holding a slice of pizza, he had a guy holding a Diet Coke. You're going on stage and you're trying to fight through all these people to get dressed.

Timberlake it was just him, he's a real class act that guy. He was great, and also the guy doesn't show up with anybody. It's just him. He's just wandering the halls and my wife visited the show and she thought like he was one of the crew guys hanging out on the set. She was like, 'Oh my gosh! Whoa!' and he was like, 'Hey, how are you?'"

Hader wasn't a total Hater, though. He did tell Stern that Mariah Carey probably had even more people in her entourage than Bieber. And he did have some compliments for young JB:

"I had nice chats with him when we were doing the scenes. He was a nice guy, a nice kid. You know he was doing the scenes and trying to do the best scene he can."

Bill Hader just returned to "SNL" as host on March 17 to promote his new HBO show "Barry." "Black Panther" star Chadwick Boseman will host SNL on Saturday, April 7.

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