Canadian superstar Justin Bieber has revealed the difference between his US and UK fans, admitting British girls have "dirtier mouths".

The teenage heartthrob was discussing his legions of loyal fans on both sides of the Atlantic.

Speaking to Fabulous magazine Bieber revealed: "The girls definitely have dirtier mouths,' reveals Justin. "In the UK, things are less...what's the word? You don't take things as seriously.  Things are accepted in the UK that aren't in the US."

He added: "Like the commercials are sexier and wouldn't be allowed in the States."

Bieber appreciates the frank nature of his UK fans though.

He continued: "It's more free in the UK. You guys are more open-minded. So the way that the UK fans approach me is different. But I've been doing this so long it doesn't shock me anymore. It's so funny though. It still makes me laugh."

Meanwhile, Bieber's rumoured ex girlfriend Selena Gomez has taken to the stage to sing a rendition of Justin Timberlake's famous break-up song 'Cry Me A River.'

Though their relationship status remains unconfirmed, it has been largely reported that the pair have split.

Bieber performed an a capella rendition of the hit song when the pair were going through a rough patch last November - and last night Gomez, 20,  took to the stage to sing the track during a show for UNICEF.

Before she began singing, the brunette beauty said: "This song definitely speaks to me".

Watch Gomez perform the song below: