What's the Biggest Surprise of the Grey's Anatomy Musical Event?

Star Sara Ramirez reveals which of her fellow castmembers will shock you with her singing talents

Sure, Sara Ramirez is the star of Thursday's Grey's Anatomy musical extravaganza—the ep all about Callie's busted brain, not to mention her imperiled baby—but she just told us that there's more to this episode than shining a spotlight on one single diva.

She said that the rest of the cast stepped up to make the ep a real ensemble performance: "Singing can be very confronting and can be overwhelming, a little intimidating if you're never done it before...[but everybody] showed up, and I was so proud of everybody—not like in a condescending way—but just like [I was] really inspired by everybody's gusto and fearlessness. Or if they had issues they worked through them and they showed up anyway!" 

So which costar shocked Sara with her standout singing chops?

Sara told us, "Chyler Leigh sings a beautiful song called 'Breathe,' and she does a beautiful job. She has never really sung in public before...We would do crazy fake runs with each other on set, really just horrible-sounding runs with each other, just to make each other laugh, and there was something about every time she did it, I was like, 'Wait a minute. You can sing. Oh yeah. All right.' But she's so shy about it. I just love her and she did a really great job."

In case you aren't yet hip to the plot twist that's making the musical possible, Sara explained, "Callie's state is such that we're seeing people behave in ways that we normally wouldn't see—like the fact that they break into song...So storylines are still developing throughout the episode with different characters, but what we're seeing is because of all the trauma, we're seeing a lot of this through her state, and it's being interpreted through her brain and her state."

"Song Beneath the Song" airs Thursday at 9 p.m. on ABC; to see Sara sing on TV before then, be sure to tune in to Good Morning, America Wednesday for a preview of her pipes.