Watch the Justin Bieber 'Saturday Night Live' Sketch That Was 'The Greatest Trainwreck Ever'

"SNL" releases the unaired video along with commentary by Bill Hader.

When Justin Bieber hosted "Saturday Night Live" in February, the teen dream got decent reviews. "He did a very respectable job," we said back then.

Little did we know that Bieber was part of one of the worst sketches in "SNL" history. But now the show has released the epically awful unaired footage from dress rehearsal, along with commentary from Bill Hader and writers Rob Klein and John Solomon.

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Hader, who left "SNL" at the end of this season, calls the sketch "the greatest trainwreck ever."

Hader plays a country singer and Bieber is his son. They're introducing a new song with an interesting sound. But the sketch goes awry from the beginning, when one of the set walls almost crushes Bieber. The pop singer looks genuinely terrified.

"That's true fear on Justin Bieber's face," Hader comments. "He's scared."

Things only get worse from there. Bieber breaks character, bad lighting casts a dark shadow over Hader's face, several cues are missed, and none of the jokes elicit laughs from the audience.

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"This guy in the front row didn't really understand comedy," Hader notes.

He and the writers point out that the sketch "killed at the table read."

After the rehearsal ended, Hader says he went backstage, where Klein and Solomon remarked, "Well, that didn't go well."

Understatement of the year!