Ariana Grande and Big Sean Sings at KIIS FM's Jingle Ball

Ariana Grande and her boyfriend Big Sean sang "Best Mistake" at KIIS FM's Jingle Ball at Los Angeles' Staples Center last Friday December 5, 2014. Ariana was in a skimpy two piece red outfit, glittering red bra top with matching high-waisted shorts. While Big Sean was wearing what guys wear when they go to 7-11.

The couple stepped onto the stage at downtown Los Angeles' Staples Center in coordinated red outfits as they treated the capacity crowd to a performance of their song Best Mistake.

She also performed with British ginger Jessie J on the show.