Ariana Grande and Big Sean sing emotional duet at Jingle Ball

LOS ANGLES , Calif., Dec. 8 (UPI) -- Grammy-nominated singer Ariana Grande and rapper Big Sean gave a steamy performance together at KIISFM's Jingle Ball in Los Angeles' Staple Center Friday night.

Grande, 21, surprised the audience mid-way during her scheduled set by inviting Sean, her boyfriend,to the stage to perform "one of [her] favorite songs." The duo then gave an emotional rendition of their single "Best Mistake," which appears on Grande's debut album, My Everything.

Grande and Sean held one another during the performance and concluded the act with a caring hug.

Rumors that Grande and Sean were dating began began in August after they were photographed holding hands backstage at the 2014 MTV VMAs. The rapper confirmed the relationship in September, claiming they were "friends for years before anything else."

Sean ended his engagement to Glee star Naya Rivera in August.