Justin Bieber thrilled fans on Sunday night by staging an impromptu performance at a concert by his girlfriend Selena Gomez.
Gomez played a gig at the OC Fair in Costa Mesa, California and the audience was stunned when she was joined onstage by Bieber midway through the show.
Bieber gave Gomez a hug before launching into a medley of songs including his track "Favorite Girl" and the Justin Timberlake hit "Cry Me A River," according to MTV.co.uk.
After the show, he took to Twitter to thank fans for their support before sending a message to Gomez telling her: "U did great tonight. Proud of u."
(Photo: Getty Images)