American singer-songwriter Ariana Grande performs during the Bambi 2014 media awards ceremony in Berlin
American singer-songwriter Ariana Grande performs during the Bambi 2014 media awards ceremony in Berlin November 13, 2014. The annual Bambi awards honours celebrities from the world of entertainment, literature, sports and politics. Reuters/Fabrizio Bensch

Ariana Grande and Big Sean were seen indulging in PDA during their performance at A Very Grammy Christmas Concert in Los Angeles on Tuesday, Nov. 18. The couple, who has been reportedly dating since August, shared some cosy moments on the stage. They held hands, huddled up and looked into each other's eye, while singing for the audience. Grande was expected to give a solo performance at the event, but Big Sean surprised the crowd by joining his lady-love on the stage.

"Her next single will be her duet with him so the label wanted him there to help promote it. Ariana and Sean didn't know about it until they were told by their respective teams," a source revealed to Hollywoodlife, about Big Sean's surprise entry.

The couple's chemistry was blazing hot as they belted out some great melodies. The 21-year-old singer looked stunning in a slinky red dress and red heels. She accentuated her look with her signature ponytail and was wearing minimal accessories.

Meanwhile, Ariana Grande's boyfriend looked dapper in a black tuxedo. He added a touch of class as he came wearing a white shirt and black bow tie.

Big Sean and Ariana are rumoured to be dating since this past summer. They have created quite a buzz around their romance, as they started dating each other soon after their high profile break-ups. Big Sean called off his engagement with Naya Rivera whereas Ariana split-up with boyfriend Jai Brooks.

Big Sean dated "Glee" star for a period of one year from April 2013 to April 2014. They announced their engagement in October 2013, but called it off for unknown reasons. Later, Rivera married actor Ryan Dorsey in a secret ceremony. Meanwhile, Ariana was in an on and off relationship with comedian Jai Brooks. She had also dated "The Wanted's" Nathan Sykes in between, during her time off from Brooks.

Grande and Big Sean will be soon filming a video for the song "Best Mistake." The lyrics of the song goes as, "Cause if the water dries up and the moon stops shining / Stars fall, and the world goes blind, boy / You know, I'll be savin' my love for you, for you / 'Cause you're the best mistake I've ever made."