The first season of HBO’s The Righteous Gemstones, a comedy about a family of televangelists presided over by Eli Gemstone (John Goodman), pivoted around a mid-season flashback episode, “Interlude,” that turned the clock back to 1989 in order to flesh out the background behind the show’s character dynamics. To achieve the de-aging effects that made Goodman look 30 years younger, VFX house Gradient Effects said, it used a proprietary tool called Shapeshifter to transform the actor’s face.

The company’s owner and VFX supervisor, Olcun Tan, describes Shapeshifter as the first tool of its kind. The company said the tool first analyzed the shape of Goodman’s face, extracting certain anatomical characteristics as layers that would be reapplied at the end of the process. That allowed artists to reshape the actor’s face without changing the original performance — and allowed Goodman to interact with objects and other people in the scene, Gradient Effects said.

You can see the results in motion (and you can watch Walton Goggins clog-dance!) in this clip from the episode:

“One of the first shots of ‘Interlude’ shows stage crew walking in front of John Goodman,” Tan said in a prepared statement. “In the past, a studio would have recommended a full CGI replacement for Goodman’s character, because it would be too hard or take too much time to maintain consistency across the shot. With Shapeshifter, we can just reshape one frame and the work is done.”

Gradient claims that it completed “nearly 30 minutes of film-quality VFX” for the show in six weeks’ time, making its technique a cost-effective alternative to approaching the same problem through motion capture and make-up effects.

Shapeshifter had previously been used on The Revenant to alter the shape of Leonardo DiCaprio’s post-bear attack face.

With locations in Los Angeles, Frankfurt and Montreal, Gradient Effects’ credits include Doctor StrangeThor: Ragnarok, and Stranger Things.

Gradient Effects: