Demi Moore and Margaret Qualley Break Down the Most Disgusting Part of Wearing Those Prosthetics in 'The Substance'

Since Coralie Fargeat's new horror film, The Substance, debuted to win Best Screenplay at the Cannes Film Festival back in May, Demi Moore and Margaret Qualley have answered plenty of questions about the many emotional layers of their character(s?) in the movie.

But what about all those layers of prosthetics?

The co-stars shared their thoughts—and a bit of personal horror—during a panel at the 27th SCAD Savannah Film Festival, which kicked off Oct. 26, 2024.

The Substance stars Moore as a TV fitness guru named Elisabeth Sparkle whose boss (Dennis Quaid) wants to replace her with someone younger—so she uses a mysterious black-market drug to create a more youthful version of herself, who goes by Sue (Qualley). If you've not yet seen it in a theater, it heads to streaming on Mubi on Oct. 31.

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We won't spoil it for those who haven't watched, and yet you only need to see the official trailer to get a glimpse of the gore. The story ultimately leads to significant physical transformations for both Elisabeth and Sue as the plot—and prosthetics—thicken. The changes are so dramatic, that both actresses spent long hours in the makeup chair to shoot those scenes.

"For me, it was anywhere from six to nine and a half hours in the chair. That really requires that you get very still, very zen," Moore says. "I would definitely say that it’s a much easier read on the paper, the script. You’re like Yes, prosthetics, oh that’s so fun. And then to have so little time to shoot. It’s a lot. It’s a lot on your body, spending that time having to be humped over.

"At the same time, we had incredible technicians and artists who created the makeup. They were extraordinary and made a very uncomfortable, difficult process as comfortable as possible. It’s just very interesting. Once it’s all on you can’t really eat or drink because it’s so delicate it will fall apart. It’s like getting used to people touching you all day—people’s hands around your face and your body, then having to find that way of letting it go so you can jump into whatever you are doing. Poor Margaret had to do it where her time getting ready was less but [she] only had one eye and one ear!"

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Qualley says it took about five hours for artists to apply her makeup and prosthetics and about an hour and a half to remove it all. Holding her head and neck at a harsh angle with lowered arms for so long was "taxing on my ... everything," she says, adding that wasn't the worst part of all.

"This is a gory detail: I am meant to be crying in a lot of those scenes. ... This is disgusting; I’ve actually not said this before: You’ve got something glued on to your face, and then you are like, OK hey cool, now I am going to have a mental breakdown. Then you start to have a mental breakdown and you’re crying, and the tears start to collect under the glue. And then the snot is collecting under the glue. And so then you’ve just got this glued-on mask of your own tears and snot, and then they’re just trying to glue it on harder!" Qualley says.

"So you’re like Oh, good! Yeah, yeah, yeah! Why don’t you just put some super glue in there and just smash my own snot against that? I like this one! Mmm hmm! You want me to do it a couple more times? That’s uh, that’s what I want to do too. That is what I was also hoping for. I am really glad that this will also take a couple hours to take off. COOL!"

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While Qualley earns laughter during her retelling, Moore adds, "I think the highlight is that [Fargeat] made Margaret be in the suit when it had my face on it."

“Ah yeah! You know when there’s a poster of her face on me? I am still in there! What the hell?!" Qualley replies.

"That was my week off," says Moore, adding she actually was off that week, which included the goriest scene of the film. "With the blood, which was 30 gallons, by the way. Thirty gallons the director herself wanted to operate with a fire hose," Moore says.

Beyond the entertainment and "visceral experience" you can expect, Moore says, the film is "awe-inspiring in that it feels like we are possibly laying down a few pieces of that pavement leading towards a cultural shift, mainly in how we are holding ourselves."

Next, All We Know So Far About Moore's Role in Taylor Sheridan's New Series, Landman