Justin Bieber roasted by Will Ferrell as Ron Burgundy

Pop star Justin Bieber was mocked by Will Ferrell in character as Anchorman's Ron Burgundy during his comedy roast in Los Angeles on Saturday (14Mar15).

The troubled singer was the butt of all jokes during the taping, with stars including comedian Kevin Hart, retired sports legend Shaquille O'Neal and rappers Ludacris and Snoop Dogg all taking aim.

Lifestyle guru Martha Stewart was also among the line-up and she referenced her own time in jail by handing out advice on life behind bars to Bieber, joking that he will "inevitably end up in prison."

The biggest surprise of the night was an appearance by Ferrell, who lampooned Bieber as his newsman character Ron Burgundy, telling the audience, "You people don't know what the hell you're talking about. As far as I'm concerned, this guy is doing it right... I always encourage people to stay classy. And what's more classy than hanging out with Floyd Mayweather?"

Bieber also addressed the crowd and made an apology for his bad boy behavior over the last few years, saying, "I turned a lot of people off the past few years... There was no preparing me for this life. I got thrown into this, 12 years old. There are moments I'm proud of and things I've done that don't define who I am. I look forward to being someone you're proud of... You have my word - I will not end up broken, pathetic, bitter or sitting on someone else's roast. I'm at a moment of change. This is a new day."

An edited version of the roast will air on 30 March (15).