Beautiful. Just beautiful. That's how Demi Lovato and Naya Rivera sound on their lushly harmonized duet of 'Here Comes the Sun' from the Beatles' 'Abbey Road.' The duo sang the song for an upcoming episode of 'Glee.'

Lovato is joining the show for a limited run as a singer named Dani who becomes romantically involved with Rivera's Santana, who is a lesbian. It's safe to assume that the ladies will likely have crackling, electro-charged romantic chemistry, since their vocals are off the chain.

Their voices are perfectly intertwined in harmony. It's truly lovely, and tugs at the strings of the heart.

Season 5 of 'Glee' premieres on Sept. 26.

Lovato, busy with Season 2 of 'X Factor,' as well, was the couch guest on 'The Tonight Show' with Jay Leno, and she spoke about her new 'Glee' role,' which is a huge professional score for the singer.

"I will be playing Naya Rivera's love interest," she said. "I'll be doing six episodes." She also revealed how she was gifted with a goat when she went to Africa. She wanted to take it and give it to her grandparents, who have a farm in Arkansas, but ultimately felt it was more useful to a Kenyan family, especially since getting the animal through customs would have been a nightmare.

For her part, Rivera spoke about practice make out sessions with Lovato before their onscreen kissing scene, saying, "I made out with her like in my trailer before we shot the scene. So then I just like warmed her up. You know what I’m saying."

Rivera's BF, rapper Big Sean, wasn't mad. He was bummed he missed it. "He was like, 'Oh man, I’m out of town, I’m jealous!'" Rivera joked.

While Lovato and Rivera are beautiful ladies, we bet their love story on the show is touching.

Watch Demi Lovato on 'The Tonight Show'