Actor Rob Lowe believes Justin Bieber is frustrated that most of his fans apparently don't care about his music.

The 20-year-old is a heartthrob to many adoring fans and Lowe experienced the same during the 1980s.

However, he said on Oprah Prime that he thinks Bieber is 'bummed out' by knowing that more fans are interested in his looks rather than his tunes.

Lowe said: "I have tremendous empathy. He makes really good music, he does, but I think he knows the dark secret, and the dark secret is 80 percent of his audience doesn't give a s**t about the music. And he knows it. It bums him out.

"They care about lemming-think, and their girlfriends and who's oohing and aahing and screaming. It has nothing to do with what he's doing as an artist. He is the guy who is standing in front at a moment that they're going through a developmental thing. It's natural, it's all great, but if it wasn't him, it would be somebody else, like it was me."

Bieber meanwhile is set to face trial on May 5 on charges of DUI, driving without a valid licence and resisting arrest.

The Canadian was pulled up by cops in Miami's beach area after apparently drag racing.

Watch Justin Bieber's recent videos below: