Justin Bieber attends Selena Gomez's 21 birthday party

Justin Bieber reportedly turned up unannounced at his on-off girlfriend Selena Gomez's 21st birthday celebrations in Malibu.

The 19-year-old singer arrived at the gypsy-themed house party on Saturday around 9pm, reported Us magazine.

Bieber, dressed in a black-and-green jacket, dark jeans and white high-tops, had a small present for the birthday girl.

"Justin flew in specifically for the party on a day off from his tour. He wasn't dressed in costume, but carried a single red rose in his hand."

The party had celebrity guest invitees like Julianne Hough, Nina Dobrev, Derek Hough, Ashley Benson and Jaden Smith, among others. Best friend Taylor Swift missed the party as she was performing at a show.