Justin Bieber
The pop star used his appearance on Saturday Night Live to apologise to fans for smoking marijuana. Reuters

Pop star Justin Bieber has publicly addressed his use of marijuana for the first time.

The 18-year-old singer used his appearance on Saturday Night Live to apologise to fans for smoking the drug in a hotel room with friends.

Speaking in the third person in a sketch in which he played the president of the Miley Cyrus fan club, he described himself as a "douche" before touching on his pot-smoking habit.

"I also heard he [me] got busted for smoking weed and he's really sorry about it and people make mistakes and he's never gonna do it again, " he said in the sketch.

The teen sensation made headlines when pictures of him smoking marijuana with a friend during a party in Newport Beach surfaced online.

The images sparked accusations that he was setting a bad example for his young fanbase.

Although Bieber did not openly admit doing drugs at the time, he sent a cryptic message to his 32.7 million Twitter followers saying that he was still young and would make mistakes.

"Everyday growing and learning. Trying to be better. U get knocked down, u get up," he wrote.

"I see all of u. I hear all of u. I never want to let any of you down. I love u. and thank u. #beliebers."