Irish star Fiona Shaw has a "disastrous" new relationship in the third series of Killing Eve... with a daughter.
The Cork actress, who plays spy boss Carolyn Martens in the popular series, which returns to our screens later this month, meets her match when her feisty offspring turns up.
Fans knew she had a son, Kenny, who is also in the secret service game and has appeared in the first two series, but not a daughter.
However, Geraldine - played by Game Of Thrones star Gemma Whelan - arrives to cause havoc as she has the opposite personality to her cold mother and empathises with everyone.
"It's disastrous," says Shaw (61) of the relationship between Carolyn and her daughter.
"It's hilarious because Geraldine is just absolutely a red rag to a bull with all of this feeling and self-help and emotional talk. It drives Carolyn mad. For all the peculiarity of their relationship, Kenny and his mum have a lot in common.
"They're both slightly obsessive and they get on very well in their silence. They didn't have to speak much. I'm thrilled that Gemma has joined the family."
Shaw told Entertainment Weekly that Geraldine has nothing to do with the spy world but kept mum about the storyline.
"She hasn't on the surface anything to do with the family business," says Shaw. "That's not her interest. You'll find quite quickly that she's the one who got away.
"But she comes back and she tries to organise the household in a more organised way, which Carolyn really doesn't like. It's good because you get the family dynamic.
"There is love there but whether there's actual liking there is a difficult thing to say. They're very different people, put it like that. So there's plenty room for complication in this."
Whelan (38) played Yara Greyjoy throughout the Game Of Thrones run after being introduced in the second series. She was recently seen in the murder thriller, White House Farm.
The new series of Killing Eve, which follows the love-hate battle between super-assassin Villanelle (Jodie Comer) and MI6 operative Eve (Sandra Oh), begins six months after series two ended with the killer shooting the spy in the back after being stabbed by her.
TV bosses revealed earlier this year that a fourth series of the show has already been ordered. Shaw won the 2019 Bafta TV Award for Best Supporting Actress playing Martens.
Several key new faces will be introduced in the new season, with executive producer Sally Woodward Gentle calling it "the most personal season" yet.
New cast members include Harriet Walter, Danny Sapani, Pedja Bjelac, Camille Cottin and Steve Pemberton.