Ludacris thinks some elements of Justin Bieber’s recent roast were completely inappropriate.

The 37-year-old rapper-and-actor attended the taping of the 21-year-old singer’s Comedy Central roasting, which took place earlier this month.

Ludacris was great friends with his Fast & Furious co-star Paul Walker before he died in 2013 and when Paul was included in jokes at the event, the musician took offence.

“It’s not one particular person, there were just certain jokes that were—and I'm not saying anything towards me—I'm just saying there were some jokes that weren't appropriate," Ludacris explained to HuffPost Live. "You know, there were some Paul Walker jokes that I didn't feel like were appropriate. And I was told and promised that they would edit those out...Some of those were over the line."

Comedy Central confirmed to Variety last week they will be cutting the Paul Walker jokes out of the broadcast entirely.

Despite his offence at the puns towards his dead friend, Ludacris found the event pretty entertaining overall.

He featured on Justin’s 2010 hit Baby and since then, the hip-hop star is impressed with how much the Canadian heartthrob has grown.

"I think he went through adolescence," Ludacris said. "You can't judge but so much when we're looking at it from an adult perspective and we're watching him literally grow up, so you have to expect him to go through some things ... We all make mistakes."

Justin’s Comedy Central Roast, which was hosted by comedian Kevin Hart, will air in the US on Monday March 30.