Former Guns N' Roses bassist Duff McKagan thinks Justin Bieber is a ''rocker'' and he was impressed by the 17-year-old star when he saw him perform live.
The rocker is impressed by the 'Baby' singer's musicianship and thinks he puts on a great live show.
He said: "Do you know what? Justin's a rocker. Man, he actually sings at his gigs, and the band's a real band, and he plays drums and he's f***ing great. Justin Bieber is a rocker for sure."
The Velvet Revolver star discovered Justin's music through his two daughters, 13-year-old Grace and 10-year-old Mae Marie - his children with his wife, swimsuit designer Susan Holmes.
And the 47-year-old rock star - who was notorious for his hard partying and drink and drug use before he got sober - has revealed he is happy to go and watch his girls' favourite pop stars with them.
He added to NME magazine: "Grace is 13 and she finds new cool stuff and she's into Justin Bieber. And I take them to every gig they want to go to. Justin Bieber concert - great. Jonas Brothers, Taylor Swift."