Casey Hynes, from Sydney, Australia, became famous earlier this year after a video emerged showing the 16 year old standing up to another student during a verbal and physical attack.
He made headlines around the world, and Justin Bieber invited the schoolboy to join him at his show in Melbourne on Monday, and invited Hynes onstage to introduce his aspirational song "Never Say Never".
Bieber told the audience, "Everybody give it up for this kid. I just wanted to say that he's very inspirational. He shows other people to stand up for what they believe in."
Taking to his Twitter page after the gig, the "Baby" hitmaker told his followers, "A kid who stood up for himself against bullying. A real life hero. We tracked down Casey and his family and flew him to the show. Thank you Casey."
Last year, Bieber recorded a public service announcement (PSA) for the It Gets Better project in a bid to prevent bullying, following a spate of young suicide victims in America.