Grey's Anatomy is nothing without its complicated family trees . Now the ShondaLand series is adding yet another branch. Maggie's mom is making her way to Grey-Sloan Memorial, reports Entertainment Weekly . Maggie (Kelly McCreary) is Meredith's (Ellen Pompeo) biological sister through their mother Ellis Grey (Kate Burton). But it's Maggie's adoptive mom who will be paying her daughter a visit this season. According to EW, LaTanya Richardson Jackson has been tapped to play Maggie's mother, Diane. New set photos reveal that Diane will hang out with Maggie at work — where the pair will run into Dr. Avery (Jesse Williams). Could Diane's visit have something to do with her split from Maggie's dad? The Grey's Anatomy newcomer has previously appeared on Luke Cage and Blue Bloods. She's also the wife of Samuel L. Jackson, just in case Grey's Anatomy needs an actor to tackle the role of Maggie's father as well. We'll find out how Maggie's mom will react to her daughter's new(ish) gig when she appears in the episode set to air February 9. Grey’s Anatomy returns with new episodes Thursday, January 26.