Demi Lovato is coming to Grey's Anatomy in an upcoming episode of the hit show.

She confirmed the news on her Twitter, and we've learned that she's totally replacing Katherine Heigl! Okay, not really, but she is filming one scene with Alex.

"Demi and Justin Chambers [Alex, husband of Izzie's character] are shooting a scene together tomorrow morning on the set of Grey's Anatomy," reports say.

The Disney star will play a schizophrenia patient in a May episode. "Everyone's super excited around here," Twittered Grey's Anatomy creator Shonda Rhimes.

Demi, who is dating Joe Jonas, herself Twittered that, "Mr. Patrick Dempsey himself wants me to give a shoutout to all you guys! hahahaha so awesome."

She also called the guest spot a "lifelong dream" and wrote "I'm so thrilled to announce that this week I'm shooting Grey's Anatomy!!!!!!!! :D AHHH!!!!"

Pretty much sums it up right there, doesn't it?

Are you excited to see Demi Lovato on Grey's Anatomy?