US singer songwriter Demi Lovato is to join the cast of hit television series Glee as the lesbian love interest of character Santana.

The former X Factor US contestant, Lovato, will star as the lesbian lover of character Santana Lopez, played by Naya Rivera, who is excited at the prospect.

She said: “I mean, she’s playing my love interest, so I’m very, very excited about that,” the 26-year-old, told MTV News.

“We get to sing a song together. It’s gonna be good. I’m excited to work with her.

“We’re bringing her to the dark side. Well, she comes in in a Beatles episode, so [we’re singing] a Beatles song. I’m excited.”

Rivera and Lovato began filming their episodes this week for Glee’s upcoming fifth season. Both stars tweeted their excitement.

“Wayyyyy too excited to be starting @GLEE this week!!!!!!! Asjfkdjshdk” Lovato tweeted on Monday.

“I can’t believe I’m going back to acting but the best part about it is that I get to act/sing with some of my really great friends..”

Rivera tweeted to say: “Wrapped a long day at Glee. Had the best time filming with @ddlovato see ya tomorrow!”

Lovato is not the first singing competition contestant to join the cast of the hit series, openly gay former American Idol singer Adam Lambert also joined the cast, it was revealed back in July.