Hugh Grant discusses The Undoing finale and the gruesome scene that was cut

*SPOILER ALERT: The identity of Elena Alves' killer is revealed in this article*

Sky Atlantic's record-breaking thriller The Undoing has resolved in a suitably dynamic finale for a classic whodunit that has kept millions hooked as the focus on Elena's killer shifted scene by scene.

On Monday her murderer was revealed to be the suave but narcissistic surgeon Jonathan Fraser, played by everybody's favourite British rom-com star Hugh Grant.

He was equal parts repellent and brilliant in the role and he told TV Line that Fraser was nearly the most evil character he has played.

He said: "Well… going back to the 1980s and my mini-series days, I was a very nasty elder brother of a champagne family in [CBS’ two-part drama Judith Krantz’s Till We Meet Again]. I sold all the champagne to the Nazis and I got whipped out of the house by Michael York and shot by the resistance. I raped poor ol’ Courteney Cox. I was horrible."

Playing evil was seasier than being the nice guy, he explained: "And I really can’t tell you why. I’m not alone; actors love it. And they dread the 'nice guy'. The 'nice guy' is a nightmare to try to play and not be boring."

Grant revealed that he knew from the beginning of production that Fraser was the killer; he wouldn't have taken the role without knowing it.

He said: "I’m not very experienced with television, but I hear that more typically the [scripts] come through as you’re filming them. It must be very difficult not knowing where your character is going to end up or where the story is going. But, in this case, we had all of the scripts before we started.

"In fact, knowing I was the killer was key to me signing on, because, obviously, that was a far more interesting part than an unfaithful husband who just pleads his innocence the whole way through."

The key to making Fraser convincing was that he "believes his own lies", said Grant.

"And I think there are sociopaths, psychopaths, narcissists like that [in real-life]. I’ve met them. They are incredibly convincing. So that was fun to play. It was also essential to play, because if he’s not convincing in those moments you have no show. The whodunit mystery goes out the window."

Grant revealed to TV Line that one especially grisly scene in Elena's murder, devised by him, didn't make the final cut.

He explained: "I don’t know what’s in the final cut, but I was doing some takes where Jonathan — while hammering away at [her head] — was spitting out a part of her brain. I don’t know if that’s still in there [It is]... And this is much worse, but after her head was [beaten into] pulp I [did a take] where Jonathan the doctor was quite interested in her brains, and he started poking around in them with his finger."

Episode six of The Undoing ends with the climactic scene on the bridge, which was as tough to film as it looked.

"There were a lot of moving pieces — helicopters, camera on drones," he said. "And it was also extremely complicated emotionally. Episode six had been the subject of so much debate. [New script] versions were emailed back and forth, especially the last section in the car. I was terrified [when we were shooting it], and I remained terrified until [the finale aired] that the whole road trip might be laughable in the wrong way."

He admitted it was a huge relief to see that people on social media thought it worked.

"I was the one who pitched [the idea of Jonathan and Henry] singing that song. That was a song that me and my cousins used to sing on holidays as kids, and I thought that might be cool as a moment of craziness. But I was terrified people would just think it was all crap."

The Undoing is available to watch on NOW TV until 30th December.

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