It's been teased for weeks and it finally arrives this Thursday: the Grey's Anatomy musical episode, titled "Song Beneath The Song," clips from which you can watch HERE.
What cans fans expect from this installment, which Shonda Rhimes says she's been "wanting to do... since we made the pilot?"
It will follow up on last week's traumatic cliffhanger, as the episode faded to white on Callie was moments away from flying through the windshield of Arizona's car. Arizona has just popped the biggest question of them all, of course.
"I think that the proposal is something that is 100 percent heartfelt, but it's just something that she sees as an answer to not feeling legitimate in this new arrangement," Jessica Capshaw tells TV Guide. "Before you can even figure out why it is that she asks Callie to marry her, they're in this horrible situation."
So... where do the songs - Capshaw and Sara Ramirez will duet on KT Tunstall's "Universe & U," for example - come in?From a semi-conscious Callie, as her colleagues treat her and communicate with her via music. Remember: the name Calliope is taken from a mythological Greek figure who was the muse of song.
"They make the connection from the get-go, so we understand why it's music that Callie's soul is speaking to her through and why she sees everybody singing," Rhimes says.
Rachael Lawrence - who has helped train members of the Glee cast - spent hours in the recording studio with hesitant Grey's Anatomy stars.
Ramirez, a former Broadway star, didn't need the assistance, of course. She will sing Brandi Carlile's "The Story" and says: "It's a wake-up call of epic proportions for Callie. What lies in front of her [after the accident] is more than just glass. It's an opportunity to fight for her life and to make sense of why her life, and her life with Arizona, is worth fighting for, if that's the case."
A full album of the episode's songs - which will include The Fray's "How to Save a Life," Kate Havnevik's "Grace" and "Wait," by Get Set Go - will be available for download on iTunes Thursday morning.