At 26, she maybe a little older than this usual fans, but Katy Perry came down with a serious case of Bieber fever at the American Music Awards last night.

The pop star was among the first to congratulate Justin, 16, after he became the youngest ever winner of the coveted Favourite Artist crown.

The fresh-faced singer from Canada also won statuettes for favourite pop album, breakthrough artist and favourite male pop artist.

Katy, who performed her track Fireworks at the show, was spotted playfully puckered up to the teen star backstage.

And she dived in for yet another kiss in the auditorium while her husband Russell Brand watched on.Katy eventually managed to tear herself away from him and headed off to the Rolling Stones VIP do along with Kelly Osbourne, Mena Suvari and Ke$ha.

‘I’m from the smallest town in the world of, like, 30,000 people,’ he told the star-studded crowd at the Nokia Theatre in Los Angeles. ‘I never thought this was possible.’

Bieber was discovered two years ago after posting his home-made pop videos on YouTube. They were seen by R&B star Usher, who helped his young protégé win a record contract.

Now the teenager is the hottest commodity in the music world. His album, ‘My World 2.0’, has sold almost two million copies since its release last year, thanks mainly to the devotion of his young female fans.

He is touring the UK next spring and recently sang one of his hits on X-Factor.

Source: Daily Mail