Justin Bieber surprised Selena Gomez by giving her a single red rose at her birthday party.

The 19-year-old singer has fuelled speculation he is back together with his on/off girlfriend after taking time out of his 'Believe' tour to fly to Malibu, California, to celebrate the brunette beauty's gypsy-themed 21st bash at the Revolve Clothing beach house on Saturday night (27.07.13).

A source said: ''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 'Beauty and a Beat' hitmaker, who was dressed in a black and green jacket and dark jeans, drove to the event in his leopard-print sports car just after midnight with his friend Jaden Smith and made a beeline for Selena when he arrived at the party.

The pair were spotted displaying plenty of affection and reportedly left the beach house together at 2am.

Several stars also turned out to help Selena celebrate after she turned 21 last Monday (22.07.13), including Julianne Hough, Nina Dobrev, Derek Hough and Ashley Benson, and the group enjoyed a selection of Mediterranean food and sank shots when the singer-and-actress' birthday song came on.

An insider added to Us Weekly: ''Everybody danced and had a blast, especially Selena, who was surrounded by her friends.''