'Disclaimer' has a shocking twist ending that centers on an intense sex scene. Star Leila George breaks down filming 2 very different versions of it.

• "Disclaimer," the Apple TV+ show from Alfonso Cuarón, aired its finale this week.
• The story ended with a twist, centered on a sex scene, that turns the rest of the show on its head.

Warning: Major spoilers ahead for the season finale of "Disclaimer."

"Disclaimer" ended this week with one major twist that changes how viewers consider the whole series.

The Apple TV+ show, adapted by Oscar-winning filmmaker Alfonso Cuarón from Renée Knight's 2015 novel, stars Cate Blanchett as Catherine Ravenscroft, a successful documentarian whose life unravels when she's sent a novel where she's the central character. The novel depicts a young mother's scandalous affair with a teenage boy while on vacation in Italy, and the ensuing tragedy that occurs when the teen drowns saving his lover's young son.

The book, called "The Perfect Stranger," was actually published by Stephen Brigstocke (Kevin Kline), a widowed retired schoolteacher and the father of Jonathan, the deceased young man at the center of the story. Stephen's late wife, Nancy, held a decadeslong grudge against Catherine after discovering erotic photographs of her among Jonathan's belongings after his death.

Consequently, Nancy filled in the blanks and deduced that Jonathan and Catherine had a secret affair, and that Jonathan's love for Catherine led him to sacrifice his life saving her son, Nicholas. She writes a manuscript about what she is certain happened between the two, and when Stephen discovers it after Nancy's death from cancer, he publishes it with the intent to take his revenge on Catherine for his son's death.

"Disclaimer" unfolds in a non-linear fashion, where we get bits and pieces of flashbacks to the fateful meeting between Catherine and Jonathan years before. Throughout the show's first five episodes, those flashbacks tell one cohesive story — that Catherine seduced Jonathan, aggressively pursuing him.

However, the penultimate episode reveals some inaccuracies with the novel's version of events (like Jonathan's girlfriend leaving Italy early because of a fight with him, not because of her aunt's death). That episode ends with Catherine and Stephen finally coming face to face, and Catherine demanding Stephen listen to her recounting of what really happened years ago in Italy.

In the finale, Catherine finally tells her side of the story: She and Jonathan never had an affair. Rather, he broke into her hotel room, threatened her and her sleeping son with a knife, and then repeatedly raped her. The erotic photos Nancy discovered weren't mementos of their relationship, but rather images that Jonathan forced a traumatized Catherine to pose for during the violent encounter.

Catherine says she'd collected physical evidence of her rape with the intention to go to the police but chose to destroy it and bury the truth after Jonathan died.

The "flashbacks" we'd seen earlier in the season, showing Catherine as a sex-starved cougar and Jonathan as her hapless prey, were not flashbacks at all. Instead, they were enactments of Nancy's imagined (and ultimately false) version of what happened between the two.

Stephen, at first unwilling to believe that his dead son was actually a rapist, commences with his plan for revenge. He leaves a barely conscious Catherine, who he'd already given drugged tea, and goes to the hospital to kill her estranged son, Nicholas, now a drug-addicted young man who's in intensive care after an overdose. He stops when an semiconscious Nicholas calls out for his mother, appearing to realize that what Catherine told him about Jonathan was true.

In the end, he burns the photos of Catherine and abandons his plans. Meanwhile, Catherine chooses not to reconcile with her husband, who immediately left her after hearing the affair story and appeared relieved to learn it was actually rape, and makes amends with a recovered Nicholas.

The 'Disclaimer' ending's twist hinges on dual versions of one sex scene, both performed by Leila George

We first see the encounter between Jonathan and young Catherine (played by Leila George in the Italy sequences) depicted as a sex scene in episode three. The truth, that it was a rape, is shown in the finale. Both versions are extensive, detailed, and graphic, and were intense to film.

According to George, Cuarón was completely upfront with her about what the role would entail, telling her exactly how he wanted to film the graphic scenes and what would be shown. Those scenes, she said, were very finely detailed in the script, which Cuarón showed her before she agreed to sign on.

For George, it was important to know that any sex scenes she was doing were essential to the story and not gratuitous. "For this job in particular, I think the whole story revolves around this evening," George said. "It's vital to the story. There's nothing in it that's not needed there. It felt very, very necessary."

She and Louis Partridge, who plays Jonathan, worked with intimacy coordinator Samantha Murray for roughly a week prior to filming the intimate scenes.

"Everyone is safe as long as you're following the moves that you've pre-planned," George said, likening coordinated sex scenes to fight scenes or dance scenes. "That's what we did."

It also helped that she and Partridge built a rapport.

"It really depends so much on the other person, and who you're working with," George said, adding of Partridge, "He's brilliant, and mature beyond his years. I felt so lucky to be paired up with him."

Having confidence when you have to take your clothes off in a room full of people also helps: "I work out a lot."

George has no idea why Cuarón called her out of the blue to ask her to be in 'Disclaimer'

George's time on "Disclaimer" was a whirlwind.

According to the actor, it all started with a "crazy phone call" from the Oscar-winning director asking her to be in his show. There wasn't a script for her to review ahead of time, so George quickly read the book it was based on in order to prepare.

From there, she had only three days to hop on a plane, jumping straight into fittings before flying to Italy. She estimates she was on set about 10 days after that initial call.

"I don't know what made him call me that day, what he'd seen, or who had really put me in front of him, I really don't know," George said. "But it was definitely one of the best phone calls I've ever received in my life."

The season finale of "Disclaimer" is now streaming on Apple TV+.