'Grey's Anatomy' Recruits 'Happy Endings' Star Casey Wilson, Rita Moreno (Exclusive)

Casey Wilson and Rita Moreno Split - H 2016
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Grey's Anatomy is about to get a double dose of comedy.

Screen legend Rita Moreno and Happy Endings favorite Casey Wilson have booked a visit to the veteran ABC medical drama, The Hollywood Reporter has learned.

In typical Shondaland fashion, details about both of their roles are being kept under wraps — other than the fact that Moreno will portray a character named Gayle, while Wilson will portray Courtney Hall. Both actresses are slated to appear in the March 17 episode of the Shonda Rhimes/Betsy Beers medical drama.

Before you start speculating — might Wilson be playing Owen's late sister? Derek's never seen but often-mentioned fourth sister? — consider the logline for the episode, titled "Odd Man Out": "Richard throws everyone for a loop when he switches the resident and attending pairings and Arizona takes a huge risk on a woman who is pregnant with quadruplets. Meanwhile, April is faced with a difficult decision, on Grey's Anatomy."

Insiders would neither confirm nor deny that Wilson — who with husband and Happy Endings creator David Caspe gave birth to a son last year — is portraying Arizona's pregnant patient. (Although couldn't you see Penny Hartz being a neurotic mother-to-be? And maybe Moreno as her grandmother?)

Grey's marks Wilson's latest TV role beyond Caspe's Happy Endings and Marry Me. Her credits include HBO's Animals, FX's The League and Hulu's Hotwives of Las Vegas as well as features Gone Girl, Bride Wars and Bachelorette Party and Bachelorette, the latter pair of which she wrote. Her casting brings her back to the ABC fold where she starred on critical darling but ratings challenged comedy Happy Endings. The actress-producer, with writing/performing partner June Diane Raphael, also has a development deal with studio counterpart ABC Studios, which produces Grey's. Wilson is repped by UTA, Odenkirk Provissiero and Ziffren Brittenham.

Moreno, best known for West Side Story, Singin' in the Rain and the Electric Company, has recently recurred on The CW's Jane the Virgin. She was a regular on TV Land's Happily Divorced and next stars in Netflix and Norman Lear's One Day at a Time reboot. She's repped by Innovative and manager John MItchell Ferguson.

Grey's Anatomy airs Thursdays at 8 p.m. on ABC. Who do you think she's playing? Sound off in the comments, below.