Now that's what we call a casting coup. Demi Lovato is set to join Season 5 of 'Glee' as part of a major storyline arc. It's an early birthday present for the starlet, who turns 21 tomorrow (Aug. 20).

While the show is reeling from the tragic death of cast member Cory Monteith, who played Finn Hudson, earlier this summer, the addition of Lovato is a major deal and should provide a needed boost of star power, as Kate Hudson and Sarah Jessica Parker had guest roles during Season 4.

TV Line reports that Lovato will play Dani, a struggling artist in NYC who is also a friend of Rachel and Santana. She will interact with the character of Adam Lambert, who is also joining Season 5. Lovato and Lambert will have several musical numbers together.

We're already trying to christen it: Lambvato? Does that roll off the tongue?

Lovato will appear in at least six episodes, starting with the Oct. 3 Beatles tribute. The show will work around her 'X Factor' schedule. That's also a Fox show, so it's all in the family and the fall programming slate will have a double dose of Demi.

Lovato has largely focused on music for the past few years. She stared on Disney's 'Sonny With a Chance' previously. She has had guest spots on 'Prison Break' and 'Grey's Anatomy,' as well.

Welcome back to serial TV, Demi!