My Big Fat Greek Wedding star Nia Vardalos and Frasier's Peri Gilpin will guest star on an episode of Grey's Anatomy, and portray sisters on the medical drama, according to The Hollywood Reporter.
Vardalos, whose TV work includes stints on Cougar Town, Drop Dead Diva and My Boys, will play Karen Winterbottom, while Make It or Break It's Gilpin will play her sibling, Marcy Winterbottom.
The bickering sisters will come to Seattle Grace in a mid-January episode.
Vardalos' casting comes nearly two weeks after Grey's and Cougar Town producer ABC Studios announced that it was developing a comedy for the actress, who is married to Cougar Town's Ian Gomez.
Gilpin, meanwhile, stars on ABC Family's Make It or Break It, but is probably best known as radio producer Roz Doyle, who kept Kelsey Grammer in line for 11 seasons on NBC's Frasier.