Question: are they actually singing in grey's anatomy

Answer: Yes, 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.''