Always one to leave us in awe, Beyoncé brought her moves and high notes to the Coachella stage on Saturday, performing "Losing You" with her sister Solange Knowles. Beyoncé couldn't stop smiling and laughing throughout the song, dancing in step to her sister's choreography. In the process, the sister act gave us what might be the most epic performance of Coachella 2014 so far. She's not the only one to make a surprise appearance, though — Jay Z also stole the spotlight with Nas! Keep reading to see video and photos of Beyoncé and Solange's duet!