Before performing in Rio de Janeiro, Brazil last night, Justin Bieber Tweeted that he had a "big surprise" planned. And he didn't let fans down -- his girlfriend Selena Gomez made an appearance and sang her song "Who Says."
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Halfway through Selena's performance, Justin joined her onstage and the couple finished the song together. After the show, Justin Tweeted, "RIO!!! CRAZY!! Thanks to Selena Gomez for helping me do something special for the crowd. A duet never hurt anybody. WHO SAYS!"
Watch Justin and Selena's duet below:
What do you think of Justin Bieber and Selena Gomez's duet of "Who Says?" Do you think they should record a song together?
Photo: Courtesy of Kevin Mazur/ABC