How de-aging tech was used in the shocking opening of 'Terminator: Dark Fate'

• "Terminator: Dark Fate" features a scene in which de-aging technology was used.
• Business Insider talked to director Tim Miller about how it was pulled off.
• Visit Business Insider's homepage for more stories.

Warning: Spoilers below if you haven't seen "Terminator: Dark Fate."

"Terminator: Dark Fate" takes place after the events of 1991's "Terminator 2: Judgment Day." That means Skynet has never been created and there's no machine-led apocalypse.

So it's time for the Connors to finally chill.

"Dark Fate" begins with Sarah Connor and her son John relaxing at a beachside eatery a few years after "Judgment Day." Then out of nowhere, a rogue T-800 Terminator, still in the past trying to fulfill its mission to kill John Connor, the savior of the resistance in the future, appears and kills John. Sarah goes to her son, completely distraught, while the Terminator walks away having completed its mission.

The scene is a shock for Terminator fans, who through the franchise have known John as the beacon of hope. But also shocking in the scene is that Linda Hamilton, who plays Sarah; Edward Furlong, who plays John; and Arnold Schwarzenegger as the Terminator look like they did almost 30 years ago. And that's because of de-aging technology.

It's a kind of special effect that has become more prevalent in movies, especially this year, as everything from "Gemini Man" to Martin Scorsese's "The Irishman" has used it.

In a recent interview, "Dark Fate" director Tim Miller explained to Business Insider how the tech was used for the scene.

On the day the scene was shot, body doubles were used to replace Hamilton and Schwarzenegger while actor Jude Collie played a younger, 1990s version of Furlong.

"They all wore these skull caps which allowed us to do a full head replacement on all three of them in post," Miller said.

Miller also said that Hamilton was on set the day of shooting to walk through the scene with her body double.

Then during post production, Hamilton, Schwarzenegger, and Furlong went to Industrial Light and Magic, which was in charge of getting their faces pasted over the body doubles' in the scene.

"We got Eddie in for a day and then Linda came in for a day and Arnold in for a day," Miller said.

This was Furlong's only involvement in the movie.

The result makes you do a double take, especially the de-aging of Linda Hamilton, which looks so good you would think it's an outtake from "Judgment Day."

Miller is proud of the scene, especially for its brevity. "The scene originally had more dialogue between Sarah and John," Miller said, but he's happy it was cut.

The scene sets the stage for what's to come in the rest of "Dark Fate." Though Skynet never causes the rise of the machines, another company does, leading to another hope for the future being chased by a Terminator. But there to save the day is Sarah Connor.

"Terminator: Dark Fate" is currently playing in theaters.