Demi Lovato is dying for fans to see her Glee cameo.

The 21-year-old singer and actress joined Chord Overstreet, Lea Michele and the show's stars for her first day of filming the hit TV musical on Tuesday.

Apparently Demi instantly got along with her new castmates.

"Gllllleeeeeeeeeeee #1stDay #LOVEthiscast!!!" she tweeted.

Demi is believed to be playing the love interest of Naya Rivera's character, high school cheerleader Santana Lopez.

The actress has yet to confirm the reports but admits she's eager for fans to see what the writers have in store for her character.

"Love my fans!!! Can't wait for you guys to see Glee!!!" she gushed.

Demi's new co-star then promptly replied on the micro-blog.

"@ddlovato gonna be amazinngggg!!" Chord wrote.

The Glee cast is coming off of a difficult few weeks following the loss of Glee star Cory Monteith, who played Finn Hudson on the series.

The actor, who dated Lea both on and off-screen, died from a heroin overdose on July 13 and his former co-stars have been working on a special tribute episode in his honour.

Naya recently admitted Cory's passing has been her most painful experience to date and coming to work in the days since has been a struggle.

"It's the worst thing that's ever happened to me. It is the hardest thing to do. It's been the worst week ever," she confessed.

Glee creator Ryan Murphy recently announced Finn's cause of death would not be included in the tribute episode and instead would be left open to interpretation.

Season five is scheduled to premiere in the US September 26.