<P> Leigh said that some actors were not "excited" about singing but still could participate in the episode . "There were certain ways in which the scenes were written, even if there was a song in there, that perhaps a line was spoken instead of sung," she said . </P> <P> A vocal coach was enlisted to help the cast . Music director Chris Horvath was recruited to arrange the selected songs for the cast . The arrangements took around two months, with vocals recorded over four days in February 2011 . Horvath praised the cast's response to the episode, noting that only four performers had "serious vocal talent," while some had "barely sung in the shower" before . Those with professional singing experience include Ramirez, who won a Tony Award for her role in the musical Spamalot, and Wilson, who appeared in the Broadway production of Caroline, or Change . Cast members's reactions toward the episode varied . Pompeo initially deemed the idea "crazy," but changed her mind following the first read - through . Recurring cast member Sunjata stated that singing was "a bit out of (his) comfort zone," but found it an "interesting challenge," and McKidd deemed it "very exciting to do something that's completely out on a limb for the show ." </P> <P> Critical response prior to broadcast was mixed . TVLine's Michael Ausiello assessed that the episode would "either be a show - stopping triumph or a spectacular failure," with no possible middle ground . William Keck of TV Guide initially had "serious doubts," which were allayed by a visit to the set, during which he listened to the soundtrack . Keck likened it to the "much - beloved early seasons of Grey's, when music played a vital role on the show ." Entertainment Weekly's Dan Snierson predicted heavy use of Auto Tune, though fellow EW writer Jennifer Armstrong was optimistic that the episode would be a success, commenting: "I have faith . I like musicals, I like Grey's . I'm rooting for this to work ." </P> <P> During its original broadcast, "Song Beneath the Song" was watched by an average of 13.09 million American viewers . It attained a 4.9 / 13 Nielsen rating / share in the 18--49 demographic, making it the second highest - rated program of the night, behind only American Idol on the Fox network . The rating was the second highest of the seventh season until that point, and a 30 percent increase from the previous episode, "This is How We Do It," which was watched by 2.4 million fewer viewers . </P>

Who sings on grey's anatomy musical episode