'Grey's Anatomy' Adds TV Legend to Cast Alongside Sister for Season 17 Episode

While most of the casting buzz around Grey's Anatomy Season 17 has been all about surprise returns, one major guest star coming up has never been on the show until now. TV icon Phylicia Rashad will guest star in the ABC medical drama's April 15 episode. She will star alongside her real-life sister, Debbie Allen, who has played Dr. Catherine Avery on the series since 2011. Allen is also one of the executive producers on the series and has directed 26 episodes.

"My sister Phylicia Rashad will appear in [Episode 12] and bring true power, fun, and grace in a role that touches a chord about the voice of the people," Allen told TVLine Wednesday. "Our cast and crew gave her a standing ovation in honor of her presence. I gave her a slice of cornbread." Catherine will appear in the April 15 episode, but will not share any scenes with Rashad, TVLine reports.

This is actually not the first time Rashad, 72, has played a part in the Grey's Anatomy universe. She voiced a character named Pilar in the Station 19 episode "Ice Ice Baby." She was not seen onscreen in the episode though. Rashad is best known for playing Clair Huxtable on The Cosy Show, which earned her two Emmy nominations. She also earned two nominations for playing the mother of Susan Kelechi Watson's Beth on NBC's This Is Us. She has a fifth Emmy nomination for her performance in the 2008 TV production of A Raisin in the Sun.

More recently, Rashad appeared uncredited as a pastor in Netlix's 13 Reasons Why. She also starred as Diana DuBois in 16 episodes of Empire. Rashad plays Apollo Creed's widow Mary Anne in the Creed movies and is expected to reprise the role in the upcoming Creed III.

Grey's Anatomy is already the longest-running medical drama in American primetime history. There has been rampant speculation that this might be the show's final season, but nothing has been set in stone. During a stop on CBS Sunday Morning, star Ellen Pompeo said she and her fellow producers are "Still trying to figure it out." Showrunner Krisa Vernoff told The Hollywood Reporter that the final episode of Season 17 is being written as though it could be "either a season finale or a series finale" in case ABC chooses not to renew the show. "I'm planning for both contingencies and it's hard and it's not ideal," she said. "It's not where I wish we were."