'Mom' Enlists Ellen Burstyn and June Squibb for Season 3

Ellen Burstyn, June Squibb Split - H 2015
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Ellen Burstyn, June Squibb Split - H 2015

The Plunkett family is about to get a bit more complicated.

CBS' third-year comedy Mom has cast Ellen Burstyn as Shirley Stabler, the estranged mother of Bonnie (Allison Janney) and grandmother of Christy (Anna Faris), The Hollywood Reporter has learned. 

"Ellen Burstyn plays [Bonnie's] biological mother, who put her in foster care when she was very young," Mom co-creator Gemma Baker told The Hollywood Reporter at CBS' TCA party Monday. "Of course, Bonnie has a lot of feelings to work through, and Christy as well. It's a difficult reunion. We're so excited Ellen wanted to do it."

Faris -- who has yet to film with Burstyn -- echoed her excitement about the guest spot. "I'm terrified...but I also feel so flattered people want to be on this show," she said. "I'm so intimidated…I'm hoping Allison will help me through the whole thing."

Burstyn won't be the only guest star slated to appear in episode three: June Squibb (Nebraska, Getting On) has been tapped as Dottie, a woman Christy thinks might be the ideal grandmother. (And yes, Squibb and Burstyn are set to share scenes.)

"That [guest spot], I can't give too much away…[but] we're so excited," Baker said. "It's going to be a powerful episode of Mom."

Mom returns for its third season on Thursday, Nov. 5, at 9 p.m. on CBS.