The Grey's Anatomy musical event is coming March 31.

It's the episode everyone is talking about (even though there's a new one the week before), and something that's "never been done before," according to Shonda Rhimes.

Basically, it will be an hour-long tribute to the music of Grey's Anatomy, with Sara Ramirez as the lead and the rest of the cast backing her up. It should be ... interesting.

Here's a nice new featurette promoting the episode ...

With a Tony Award winner in the cast, it's no surprise that she (Ramirez) receives the bulk of the solos on the drama's first musical episode, The Hollywood Reporter notes.

She sings lead on Kate Havnevik's "Grace" and Brandi Carlile's "The Story" and shares lead duties with her on-screen lover, Jessica Capshaw, on KT Tunstall's "Universe & U."

The show will feature nine songs closely associated with the show.

Follow the jump for more details courtesy of THR ...

Chandra Wilson, who starred in Caroline, or Change on Broadway, sings on Get Set Go's "Wait." Only one of the songs, Gomez's "How We Operate," will feature a male lead.

That would be the awesome Kevin McKidd, who portrays Dr. Owen Hunt (who, interestingly, hadn't been introduced on the show at the time of that particular song's airplay).

Then, the talented ensemble of Ramirez, McKidd, Daniel Sunjata (Eli), Scott Foley (Henry), Justin Chambers, Chandra Bailey, Kim Raver and Capshaw gets two numbers:

• The Fray's "How to Save a Life"
• Jesus Jackson's "Running On Sunshine"

A video of Ramirez, who won her acting Tony for the musical Spamalot, McKidd and Bailey singing Snow Patrol's "Chasing Cars" is featured in a promo for the drama.

Creator Shonda Rhimes and director Tony Phelan had the songs selected and written into a script in November when Chris Horvath was brought in as music director.

He spent two months on arrangements and rehearsing; the vocals were recorded over four days - the episode took 2-3 times longer to cut than usual, McKidd says.

"When we started I knew we had four people who had serious vocal talent, some had a of experience and some had barely sung in the shower," Horvath said.

"There was some pushback, but I was impressed by how everybody responded."

Capshaw, for example, worked with a vocal coach and came up "with some really cool qualities" in her voice, Horvath said. He was also impressed with Chyler Leigh.

Horvath, a composer, producer and arranger, is putting the finishing touches on the soundtrack, which will be digitally available on March 31 when the episode airs.

Are you excited for it or what?

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.