Pop star Demi Lovato is set to make a cameo appear on popular musical TV show Glee.

The 21-year-old X Factor judge will make a guest appearance playing a love interest for Naya Rivera's lesbian character Santana Lopez.

Speaking to Gossip Cop at the VMAs on Sunday, Rivera said: "She's [Demi] playing my love interest so I'm very, very excited about that.

"We get to sing a song together . . . I'm excited to work with her. We're bringing her to the dark side."

Lovato chose not to attend the music event over the weekend to hang with her on/off boyfriend Wilmer Valderrama in Disneyland.