'Grey's Anatomy': Watch Casey Wilson Make Her Debut (Exclusive Video)

Casey Wilson has checked into Grey Sloan Memorial.

The Happy Endings fan favorite will make her Grey's Anatomy debut during Thursday's episode, and The Hollywood Reporter has the exclusive first look.

The clip reveals that, as THR suspected, Wilson is portraying Courtney Hall, Arizona's (Jessica Capshaw) patient who is pregnant with quadruplets. The actress is currently slated to appear in just the one episode — which will also feature screen legend Rita Moreno in a guest role as Gayle. (Details on Moreno's role are unclear, though our money is on Courtney's grandmother.)

Thursday's episode, titled "Odd Man Out," will also see Richard throw everyone for a loop when he swaps the resident and attending pairings, while April will continue to struggle with whether or not to tell ex-husband Jackson about her pregnancy.

For Wilson, meanwhile, Grey's Anatomy serves as a brief detour before production on ABC comedy Hail Mary begins. She will star as a small-town mayor named Mary who fakes a miracle in a bid to get out of hot water with the mafia.

Check out the clip, above, and hit the comments with your thoughts about whether Wilson's Courtney will have her own happy (pregnancy) ending. Grey's Anatomy airs Thursdays at 8 p.m. ET/PT on ABC.