Bill Hader has Justin Bieber on top of his mind as the worst musical guest on Saturday Night Live, he reveals straightforwardly.

Hader and Jay Pharaoh were both guests on Watch What Happens Live with Andy Cohen and talked about their time on SNL. A caller asked the two who they think was the worst-behaved celeb host or musician guest from the show.

Hader answered first and said that it was Bieber and gave much less than what could suffice for people to know the whole story.

"Everybody's usually on great behavior. Bieber is the only one in my experience ... he just seemed like exhausted or just at the end of a rope," Hader explained.

Justin Bieber's 'SNL' Stints

It can be remembered that the Despacito singer had been on SNL for three times already. The first one was in 2010 when he performed, the second in 2013 when he performed and hosted the show, and in 2012 when he made a cameo on a short film.

Hader was with SNL from 2005 to 2013, Pharaoh from 2010 to 2016. On the recent revelations about Bieber, it wasn't entirely a shocking headline.

In August 2014, Hader already made the public know how he felt about the Canadian crooner. The comedian was blatant of his sentiments about Bieber and even pointed out he didn't enjoy the time with the 24-year-old.

"I really didn't enjoy having Justin Bieber around. He's the only one who lived up to the reputation. I think that's the only time I felt that way in eight years," Hader said.

Earlier that year, Hader also opened up about how Bieber was off-cam. Apparently, the singer came to the set with a huge entourage, and the Barry star was quick to poke fun at the pop star for that and even compared the young star to another Justin, Timberlake, who came without a train of retinues.

Hader narrated how he found it hard to inch his way to get dressed, as the crowd consisting mostly of Bieber's group were there. Of the 20 guys he was with, one was holding the star's pizza while another one his beverage.

To be fair, it wasn't at all beef that Hader divulged. It turned out the SNL alum found Bieber a "nice guy," whom he got the chance to talk with in scenes.

Of late, Hader made quite a comeback on SNL after playing fan-favorite Stefon again. Fans were also vocal about their giddiness over his iconic character's appearance.