Betty Buckley
Betty Buckley has been cast in the recurring role of Patricia Arias in Season 3 of “Supergirl.” Pictured: Buckley sings onstage at “Trevor Live” held at The Hollywood Palladium on Dec. 2, 2012 in Los Angeles. Getty Images/Frazer Harrison

TV legend Betty Buckley has joined the cast of “Supergirl.”

According to TV Insider, Buckley is set to appear as Patricia Arias, Samantha's (Odette Annable) adoptive mother, in Season 3 of the CW series. Described as “honest but stubborn,” Patricia has been estranged with Samantha since the latter became a teen mom to Ruby (Emma Tremblay). But their relationship is made all the more complicated by the secrets Patricia holds.

While those secrets remain unclear, it’s possible that Patricia knows something about Samantha’s real origin. As previously reported, Samantha has no clue that she’s actually a villain in the making. “When we meet [Season 3 big bad] Reign, she’s just a woman,” executive producer Andrew Kreisberg told Entertainment Weekly. “Her name is Samantha and she’s a single mom, and she has no idea that she is Reign; she has no idea that she was the baby in the pod at the end of last season, so the journey that she takes this season is watching her realize her heritage and see how it manifests.”

Buckley will make her first appearance as Patricia in Season 3, episode 7, titled “Wake Up.” In an Instagram post announcing her casting, Buckley revealed that the episode is set to air on Nov. 20.

Buckley, who won a Tony Award for her role as Grizabella in the original Broadway production of “Cats,” recently guest starred on NBC’s “Chicago Med” and HBO’s “The Leftovers.” The 70-year-old actress is also known for playing Sandra Sue “Abby” Abbott Bradford on ABC’s “Eight is Enough” from 1977 to 1981.

Buckley is the latest addition to the growing list of series newcomers in Season 3 of “Supergirl.” In addition to Annable and Tremblay, other previously announced new cast members include Adrian Pasdar as ruthless real-estate developer Morgan Edge; Yael Grobglas as DC villainess Psi; Carl Lumbly as J’onn J’onzz’s (David Harewood) dad M’yrnn J’onzz; Chad Lowe as cult leader Thomas Coville; Amy Jackson as Saturn Girl; Erica Durance as Alura Zor-El; and Izabela Vidovic and Olivia Nikkanen as young Kara (Melissa Benoist) and Alex (Chyler Leigh).

“Supergirl” Season 3 premieres on Monday, Oct. 9 at 8 p.m. EDT on The CW.