Dame Harriet Walter found the idea of getting up on stage "horrible" when she was a child, but after being forced into doing a small part by her teachers, the Londoner realised why she had felt so apprehensive.
"I wanted to do it and I didn't want to be bad," she says.
Decades later, the 69-year-old is an award-winning actress with several huge films - Sense And Sensibility, Atonement and The Governess - and TV roles, including five years on Law & Order: UK, under her belt.
Her latest project is the Sky Atlantic drama The End, in which she plays Edie, a widow who is passionate about her right to die.
After decades of depression, she tries to end her own life but fails disastrously.
Her daughter Kate (Frances O'Connor), who emigrated to Australia years before, decides to move her to a retirement village Down Under so she can keep her alive.
Edie is also a breast cancer survivor and in the first episode we learn she had a double mastectomy.
Walter, who began her acting career in 1974, admits it was at times a difficult part to detach herself from.
"I think there were only a few occasions where that really got to me. It was usually around the physical deformity, having to wear a prosthetic," says the star, who has performed in various Royal Shakespeare Company productions.
"I think for all women, so much of your upbringing and your sense of your self is how you look, whether you like it or not. In reality, I was having to look like that, so I deliberately used whatever I was feeling about that to get me inside Edie's head. I could take it off in the bath - she can't.
"Wherever her head can go, when she's having fun or a drink, this is the reality that she comes home to in the bathroom mirror.
"To get that was quite bleak. Using your imagination about what that would be like was quite a downer.
"In a play you have hours of relentless tragedy, whereas in a TV series you get to come off every five seconds, have a drink of water and josh around with people, so it's not quite the same. Everyone around you is being quite jolly. You say, 'This is only a show, it's not really me', and you come out of it quite easily."
Walter, who is married to the American actor Guy Paul (in 2004 her former fiance Peter Blythe died of lung cancer before their wedding), notes she doesn't have very much in common with Edie.
"But there are certain characteristics I can identify with. I can be quite sort of snooty, stand-offish and self-protective in social situations," she admits.
Reading the script, she also saw bits of her grandmother in the character.
"She was quite judgmental of other people and watched people but didn't participate. But then you'd suddenly hear her cackling about something and you'd realise she'd had quite a naughty life really," she says.
"So, she's not very like Edie, but there's a bit of English upbringing in which is it's improper to talk about yourself or indulge yourself and, actually, what you're longing for is to talk about yourself."
Walter, who we will also see in the ITV drama Belgravia in the near future, is a relaxed interviewee, upbeat and engaging. She's also forthcoming with her opinions.
Discussing how the medical world might respond to the show and its exploration of euthanasia, she says: "If it was my job as a doctor to make those decisions - or rather, it isn't a decision, it's a sort of laid-down parameter that they can't cross - I think it would be quite hard to watch this series. Not just because of the material, but because I suppose I would fear what the public would learn about it. It's sort of best to let sleeping dogs lie.
"I'm not saying the whole world is going to be changed by The End, but a cultural shift is happening anyway."
Another theme the show covers is the issues facing transgender people.
Kate's eldest child Oberon (Morgan Davies) is in the process of transitioning.
It's something Edie struggles with at times.
"I get a bit nasty," Walter explains. "I think it would be a lot to expect a woman like that to understand what's going on... she's so repressed it comes out nastily.
"It's not too ludicrous. If it was really ludicrous then we would be sending up that fear and doubt.
"The fact that's more important is that she quite obviously shifts her position without politically stating it, just by demonstrating on all fronts she wants to be needed.
"When Oberon needs her help and she can give it, she absolutely loves that."
There are also plenty of humorous but emotional scenes between Kate, a doctor specialising in palliative care, and Edie as we learn more about their fraught mother-daughter relationship.
"It's not often the focus of dramas. Father-sons, father-daughters have dominated and there's so much still left to explore in that area.
"My mum and I got on fine, but I had struggles in a different way so, you know, it's never quite clean cut and easy."
She recalls how writer Samantha Strauss calls Kate part of the "sandwich generation" who have to look after their children and their parents, "plus she has to look after patients".
"By contrast, it taught me what Edie wasn't and what she wasn't doing and what she'd avoided and what she'd been," says Walter.
"She feels guilty that she hasn't been more useful or helpful or a better parent.
"When she gets any chink of hope that she can show that she is useful or caring, she grabs it, which I found rather moving because it's like if you give someone in old age a chance to change, it's rather wonderful."
The End launches on Sky Atlantic on Monday