The Westworld scene featuring a young Anthony Hopkins that left fans stunned

Anthony Hopkins in Westworld. Photo / Getty

Warning: This article may contain Westworld spoilers.

Fans of the blockbuster show Westworld were left in awe after the most recent episode featured a digitally de-aged version of Anthony Hopkins.

The 78-year-old actor plays Dr Robert Ford in the show about a futuristic theme park populated by artificial beings.

And fans couldn't believe their eyes when a flashback scene featured a much younger version of Hopkins in the third and most recent episode which aired yesterday on Foxtel in Australia.

Here's what Hopkins normally looks like in the show:

Sir Anthony Hopkins from Westworld. Photo / Supplied

And here's what he looked like in the flashback scene:

A digitally de-aged Anthony Hopkins in Westworld.

And just for fun, here's what Anthony Hopkins actually looked like in real life in 1969:

Anthony Hopkins in publicity portrait for the film 'The Looking Glass War', 1969.

Fans took to Twitter to express their amazement at the flashback scene:

However they created that young Anthony Hopkins Face on #WestWorld, that was some highkey witchcraft!

— ☔DAKrólak ☔ (@dakrolak) October 17, 2016

This Young Anthony Hopkins CGI in Westworld is fantastic and creepy as hell

— Sean Sanders (@seanjsanders) October 17, 2016

Holy cow, Westworld did an incredible job making Anthony Hopkins look young. I'm amazed.

— Lisa 🐝☀ (@Queen_Beeson) October 17, 2016

So how did they do it? Westworld's visual-effects supervisor explained the process toThrillist.

"We took a scan of Sir Tony and used that as our base," Jay Worth said, "and then used a ton of photography and reference to figure out what we wanted him to look like".

Once they'd created a CG version of Hopkins' face, they transferred it onto the body of a stand-in.

Pretty cool huh?