Justin Bieber had a special surprise in store for all his fans at Captial FM's Summertime Ball yesterday (June 9th, 2012). He brought out his protegee Carly Rae Jepsen, and the two sang a duet of her hit "Call Me Maybe." After the performance, Carly took to twitter to thank Justin personally. She wrote, “Big thanks to @justinbieber for EVERYTHING! #CapitolSTB playing Wembley Stadium was unreal!” and posted the above picture.

You can watch a video of their performance below!