The two have been spotted on various date nights, including a helicopter ride, but Selena finally made an appearance on stage at Justin's concert in Rio de Janeiro, Brazil on Thursday night.
Justin said on stage, "So when someone tells you that you're not perfect, this is what you say." His band then began to play "Who Say" and Selena emerged to sing her hit single, later on getting some help the Biebs.
After the show, Justin tweeted, "RIO!!! CRAZY!! thanks to @selenagomez for helping me do something special for the crowd. a duet never hurt nobody. WHO SAYS."
Also, while on tour, Justin gave fans a sneak peek of his holiday song "Mistletoe." Sounds a lot like "I'm Yours" by Jason Mraz if you ask us...