Justin Bieber's friends surprised him with a classic car ahead of his 21st birthday.

A source said the Canadian heartthrob's close pals, who are also his business partners in the selfie-app Shots, spent approximately $20,000 getting the car completely restored over the past few months.

Justin was clearly thrilled with the gift as he spent much of last night driving it up and down the Sunset Strip in Los Angeles, according to gossip website TMZ.com.

The insider said the car looks similar to the one that features in the opening credits of 'Entourage,' which was one of Justin's favourite TV shows.

The singer is gearing up to star in a Comedy Central Roast as part of his birthday celebrations, during which a number of comedians including Kevin Hart will poke fun at him.

The 'Confident' singer recently begged his long-time nemesis Seth Rogen, who previously branded him "a piece of s**t" and admitted he hates the star, to participate in the show, which will air on March 30.

He wrote on Twitter: "@Sethrogen all I want for my birthday is for you to roast me. I took the twitter bashing please make my bday and do it in person. Thanks.

"@Sethrogen I would have emailed u but this is the only electronic communication with u that doesn't scare me. Hope to see u at the roast (sic)"