When it came time to cast Annalise's mother on How to Get Away with Murder, Viola Davis called on a little help from a friend: her co-star in The Help, Cicely Tyson.

"I just learned that!" Tyson tells TVGuide.com. "I wasn't aware of that when I accepted the role. I was told that she was the one that asked for me. ... I will be eternally indebted to her for giving me the opportunity to just be able to walk out with her in this role, to be able to play her mother ... is a gift that I will treasure. I have so much respect for her, not only for her art, but for her values."

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That lovely, warm sentiment isn't mirrored at all in Annalise's relationship with her mother Ophelia. To say the two have had a rocky relationship, one exacerbated when Annalise married Sam (Tom Verica), would be an understatement. So ,when Annalise — after framing her lover Nate (Billy Brown) for Sam's murder — phoned her mother at the end of last week's episode for a literal shoulder to cry on, it was always a last resort.

"If I could describe Ophelia, I probably would not have been able to play her!" Tyson says. "What happens secretly between mothers and daughters through time can be quite painful. I don't know a mother who has had a daughter who has not at some time during their relationship had some kind of conflict — some minor, some major, some solve-able, some never solve them. I thought [the latter] was the way our relationship was going to go. Annalise has achieved so much since she has left my home, I thought I would probably never see her again — I never hear from her. So when I receive a telephone call that says, 'I need you. I can't tell you,' even at this point, those words overwhelm me and I was happy to meet with her. I, needless to say, was disturbed by her state and I hope that in some way I would be able to lift her out of it."

That state is a seemingly inconsolable fetal position, proving that even the toughest, fiercest criminal defense attorney this side of the Mississippi can be reduced to a defenseless little girl who just needs her mommy from time to time. But before comforting her daughter on Thursday's episode (10/9c, ABC), Ophelia needs to know one thing. "Did you do it? Kill Sam?" she asks Annalise, as seen in the promo. She asks it so nonchalantly, as if Annalise blew an 11 p.m. curfew, that one might think she knows what her daughter is capable of.

"One of the things about Ophelia is that she's very open and honest, especially where her child is concerned. ... You may refer to her as tactless, but she says exactly what's on her mind," Tyson says. "She had warned [Annalise] about this man she was going to wed. And now he's dead. They have not yet been able to find who's responsible. She is concerned that it could've been her daughter. She wants to know and it doesn't matter if she thinks she did it. Mind you, she says to her, 'Doesn't matter to me one bit whether you did it or not. I'm not the judge. I just wanna know if you did do it.' She supports her no matter what. She's a mother!"

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Once Annalise gives her an answer, Tyson says that Ophelia begins to mend their relationship, which will offer another peek into Annalise's deep, scarred past: Ophelia acknowledges an incident involving Annalise's uncle that started their rift in the first place. "Annalise doesn't know how much her mother knows about what she's been going through," Tyson says. "So, when she's able to allay any anxiety Annalise has about whether her mother knows or doesn't know, that's when she begins to try to soothe her daughter. When Annalise learns that her mother knows what her uncle did ... it really destroys her. When her mother explains what she did in an effort, in some way, to ease the strain between them, she realizes her mother loved her enough to do what she did."

By the episode's end, mother and daughter are "absolutely" closer, Tyson says. Ophelia's only a one-time guest spot for this season at least (the season finale's next week), but the Tony- and Emmy-winning star "would love" to return — if only just to work with Davis again. The two did not share a scene in The Help, which earned them a Screen Actors Guild Award for Best Ensemble, so this was the first time Tyson has worked with Davis, who has frequently sang the praises of the legendary actress, most notably in her SAG Best Actress speech for The Help.

"I got to know her casually from being on the set [of The Help], but that was the extent of our communication," says Tyson, adding that she's been watching Murder because of Davis. "After the movie was over, she flew all the way from California to New York to see me in The Trip to Bountiful. Whatever interviews she did, she always mentioned me very highly as someone who at some time or another in her career gave her hope that there was possibility to succeed. So, to actually work with her is a joy."

How to Get Away with Murder airs Thursdays at 10/9c on ABC.