Hugh Grant on how he 'couldn't say no' to latest project The Undoing with co-stars Nicole Kidman and Donald Sutherland

"I feel marginally less bad about being an actor now than I did in 2003 - that was a low point," reflects Hugh Grant cautiously.

The 60-year-old British actor is referring to a comment he made nearly 17 years ago in Paris, solemnly declaring he had made a mistake by taking up acting.

"I've almost enjoyed some of the acting I've done in the last six or seven years, which is very unlike me," he muses.

"It's been very nice to break free of having to be, you know, leading man in love."

The original comment came at a time when Grant starred as the fictional British Prime Minister in hit romantic comedy Love Actually, one of a string of film roles that saw him typecast as a romantic lead.

But with his latest on-screen project being an altogether darker affair, the Hollywood actor now seems set on veering away from the very roles he built his career upon.

"This one I couldn't say no - I mean I'm always looking for a reason to say no to jobs but I couldn't say no, the pedigree was too... it was too classy, the whole thing."

His latest acting endeavour sees him star alongside on-screen wife Nicole Kidman, Donald Sutherland, Edgar Ramirez and Matilda De Angelis, as part Sky Atlantic's dark new thriller The Undoing.

"I was all ready to be intimidated by Donald Sutherland, he's a kind of icon, but he turns out to have a mental age of about six, he just likes jokes about bodily functions," quips Grant with a smirk.

A whodunnit of impressive proportions, the script is penned by David E Kelley, the talent behind HBO series Big Little Lies, and is based on the novel You Should Have Known by Jean Hanff Korelitz.

Headed up by Night Manager director Susanne Bier, the meandering storyline sees both Grant and Kidman's characters grapple with grief, shock and confusion after a young mother is found dead following a private school fundraiser.

It's a tale that distinctly echoes that of Big Little Lies, one that leads countless lives to unravel as a steady stream of revelations bubble to the surface.

"I suppose you could look at it in two ways," says Grant of the meaning behind The Undoing's title.

"One is they've done a life for themselves, these people, and it all gets undone. That's perhaps the most obvious.

"But I also think it's, for Grace, for Nicole's character, it's about can you undo what has happened, because she is, you could argue, still in love with me despite the fact I've betrayed her."

Unveiling further details of the plot could lead to the cliff-hanger unravelling in a matter of moments, a factor Grant clearly finds enjoyable.

"It's very difficult but certainly one of the appeals of the whole project, what might be lurking beneath," he continues of his reasoning behind taking on the role.

"I think at some point I did read the novel, but I realised we diverge quite wildly from the novel after the very beginning, really. So there's not much correlation in this particular case.

"I think Harold Pinter had a phrase about The Weasel Under The Cocktail Cabinet and I suppose it's that really. What appears to be a pretty perfect kind of existence for these people turns out to be fractured by very dark forces."

Filling in the gaps through the eyes of Kidman's character, Grace, a statuesque psychotherapist and mother of one, the audience finds themselves questioning the charm of Grant's character, Jonathan, a highly regarded children's oncologist.

It's a distant cry from Grant's forlorn, lovestruck roles of the past; swapping romance for a dive into the human psyche that the actor claims to find rather enjoyable.

"I actually did try to put layers in all those romantic comedy characters, it was just harder," he says.

"For some reason, evil or screwed-up people are easier to act and more fun to act and always more attractive to audiences.

"I really don't know why exactly. I think possibly somewhere inside of us we know that we're all evil and we respond to evil... whereas niceness is possibly just a veneer that we put on top of our evil natures to make us fit in and is sort of, less attractive, less fascinating."

The television project proved a change of pace for Grant, who notes the filming schedule "was really long" compared to that of his usual feature films.

"I'm used to just doing films, which are 10 weeks maybe, this went on for six bloody months," he declares.

"I remember enjoying the last day very much and I think I horrified people by giving everyone cigars - including the boy who played my son, Noah. He loved his cigar - but I don't think his mum liked it much."

The Undoing is a series that traces a dark and intense trail of destruction - one you'd think might have some long-lasting effects on the cast, particularly given the immersive nature of acting.

"It is pretty dark," remarks Grant. "There's no therapist - except now, studios are obliged by their lawyers to put some kind of therapist on the set when you do sex scenes," he says.

"Every time you're about to - " he pauses, searching for the right word.

"They've always been difficult anyway, sex scenes, they're kind of awkward, but then in the middle of all this, as you're taking your clothes off, some woman comes up and says, 'Hi, I'm the counsellor for the sex scene; are you comfortable with what you're going to do?'

"They're all desperate not to get sued now, studios. But no, no therapy... we all became immensely depressed," he concludes with a smirk.

The Undoing will be available weekly on Sky Atlantic and NOW TV from October 26.