Julie Graham doesn't pull any punches when asked about the appeal of her latest TV show.
"Apart from the fact that it was a big, stonking lead in my 50s?" says the 54-year-old Scot, laughing loudly.
Penance, a three-part thriller that will air on Channel 5 over consecutive nights, is inspired by the novel of the same by Kate O'Riordan, who also wrote the script.
It follows Rosalie (Graham) and her husband Luke (Neil Morrissey), who are struggling to cope following the sudden death of their teenage son.
When their surviving daughter Maddie (Tallulah Greive) attends a bereavement counselling session with Rosalie, they meet Jed (Nico Mirallegro), who has also suffered great loss.
A mysterious figure, he and Maddie grow close - and by the end of the first episode you'll be hooked as you start to question Jed's intentions.
"I just loved the themes, the fact that it was about grief and passion and loss," elaborates bubbly Graham.
"I loved the fact that it was dark, and it was tense and taut and psychological, and there were lots of twists and turns in it."
Graham has her own experiences of grief. She has spoken publicly before about the death of her then husband Joseph Bennett, also the father of her two daughters, back in 2015.
But, she notes, "losing a child is a very unique grief". So, she went to a grief counselling session as research for the role.
"I did look up a group that dealt specifically with child bereavement, but I felt like a fraud and I felt like I didn't want to do that because I didn't want to then go and be a voyeur. It just didn't feel appropriate.
"So, I went to another just general bereavement counselling session because I am bereaved and so I felt like I was there legitimately.
"There were a couple of people there who'd lost children. It was a very particular, all-consuming grief in the same way that a lot of other grief isn't. That was very useful because it just felt like it was singular and palpable in some ways. It was visible."
For Graham, who has starred in hit shows such as The Bletchley Circle, William and Mary and Shetland, the character of Rosalie was unusual "because she is a woman of faith".
"You don't really see that - a professional woman who also has this very strong religious faith," she says.
She also loved the relationship Rosalie has with her priest, Father Tom, who is played by Art Malik.
"My mother was a dyed-in-the-wool atheist, but one of her really close friends was a priest and they used to wind each other up. She used to say, 'Oh, there's no such thing as God', and he'd get all kinds of upset and say, 'Well, you won't be saying that when you're in Hell'.
"They had this lovely, jokey, supportive relationship and it reminded me a lot of that relationship with Father Tom."
Not that the show made her think differently about her own beliefs.
"I don't have a faith," she declares. "I respect anybody who does have faith and I'm sure it brings you a great comfort. I mean, sometimes I wish I did, but I'm not a religious person at all.
"I would say I am spiritual and I certainly believe that there are things outside of our ken, but I don't believe in God as such, so for me that was an interesting place to put myself in as an actor."
Back to the topic of under-representation in TV and film, and Graham is mulling over what can be done to change things.
"The solution is casting directors and writers and commissioning editors saying, 'We want to cast this 50:50.'
"We're not asking for anything more. We're asking for equal representation on screen, not just in male/female, but across the ages as well."
Of her own recent experiences with casting, she recalls: "In the last year, I've been up for two jobs where it was a multi-sex part. It was a psychiatrist and they saw men and women for the part.
"It just so happens that the part went to a man, but that's because it went to the better actor, and I don't mind that - they just have to go, 'Why couldn't that part be played by a woman?'
Last year, Graham married 38-year-old Davy Croket, a Belgian skydiving instructor.
When asked if we should see more women with "toyboy relationships" on screen, she's not afraid, once again, to speak her mind - but remains friendly and chatty while doing so.
"Well, first of all, I think we've got to stop calling them 'toyboy relationships' because I think that is demeaning in itself," she suggests, matter-of-factly.
"I think it should just be a norm. I'm married to a younger man and he's constantly called my toyboy in the press. It's so irritating, not only for me but for him as well."
Rosalie has some erotic dreams in the first episode of Penance.
But the way they filmed the scenes was "very precise - like a jigsaw", Graham explains.
"It's like choreographing a dance and it absolutely should be like that because then everybody feels safe and nobody is being exposed in that way."
It's starkly different from experiences she had filming intimate scenes at the start of her career, when she was left "feeling desperately uncomfortable - and not just me, but the other actor, and actually the crew".
"You stop being an actor and start being quite an insecure person," she confides.
"I worked with a director called Michael Winterbottom and I had to do a quite intense scene with Christopher Eccleston, and how Michael worked, it was very choreographed, and so I learnt a big lesson from that.
"And whenever I've had to do that stuff, I've always said, 'We're having a meeting about this'.
"But in this day and age, I have to say that is very welcomed by everybody."
Penance airs over consecutive nights on Channel 5 from Tuesday, March 17