Justin Bieber -- Apologizes for Smoking Weed

Justin Bieber used his platform as host of "Saturday Night Live" to apologize to his fans for being photographed smoking weed ... but he did it in character.

During a sketch entitled "The Miley Cyrus Show," Bieber played Miley's biggest fan. After lobbing a few insults at himself, Biebs, while still in character, says (of the real Biebs), "I also heard he got busted for smoking weed. And he's really sorry about it. And people make mistakes. And he's never gonna do it again."

Bieber never commented directly on the pics ... until last night .. and in the third person.