On Monday, Variety reported that Henry Cavill’s mustache would have to be digitally removed in post-production for $25 million worth of “Justice League” reshoots – instantly making Cavill and his mustache the butt of many jokes.

But it’s not particularly funny for the visual effects team that has to deal with it. In fact, it’s probably going to take a lot of work, according to VFX artists interviewed by Business Insider.

Cavill is contractually obligated to keep the mustache he grew out for his “Mission: Impossible 6” role while filming. Unfortunately, the reshoots for “Justice League” happened to coincide with Cavill’s “Mission: Impossible” shooting schedule. So Cavill and his “Justice League” coworkers had a problem.

The solution: remove Cavill’s mustache with some movie magic.

This has sparked a lot of laughs, especially on Twitter. Here’s a sampling of some ‘Mustache Superman’ tweets:

Mustache Superman is canon pic.twitter.com/TCpJEJnOXy — Dave Itzkoff (@ditzkoff) July 24, 2017

I now refuse to see #JusticeLeague if Superman doesn't have a mustache pic.twitter.com/oQS6b8xdKD — absolute fantasy (@matherao) July 25, 2017

Tried to do a little sketch of Mustache Superman and it's basically Freddie Mercury pic.twitter.com/1lKrqqKs4e — Cameron Stewart (@cameronMstewart) July 24, 2017

Cavill even responded to the “Justice League” mustache controversy with an Instagram post making fun of his facial hair:

The mustache controversy may be amusing to the denizens of Twitter, and Cavill himself, but how much of a pain was it for the studio?

To understand the scope of the work involved in digitally removing Cavill’s mustache in post-production, we contacted prominent visual effects company The Mill. Anne Trotman, Lead 2D Artist, and Dave Fleet, the Head of 3D at The Mill, answered our most pressing mustache removal questions.

How common is it for a mustache to be removed in post-production?

As it turns out, having facial hair removed in post-production is far more common than you might think.

“Yes! It’s very common to be asked, particularly on beauty projects. Sometimes celebrities might be shooting a commercial, but need to keep their facial hair for a film, so can’t shave on set. Also for different global markets these days some clients need alt versions,” Trotman explained.

The difficulty of removing a mustache depends on the techniques needed.

Trotman said that from a 2D perspective, the mustache removal process wouldn’t be too hard: “We are using grading techniques as it’s not that imposing. If it was on a man, we paint a clean top lip and track that onto the face.”

However, Trotman pointed out that the degree of work involved in removing a mustache really depends on how much the actor is moving in a scene. If an actor is moving his head around, as opposed to just looking into a camera, 2D and 3D techniques may need to be employed.

“If the head moves in perspective, this would need to be achieved with 3D and 2D techniques. If the talent is facing the camera straight-on, we can use 2D techniques,” Trotman clarified.

Fleet explained that from a 3D perspective, depending on how much facial hair needs to be removed, the breadth of work involved can be difficult, and could potentially include digitally rebuilding an actor’s face.

Fleet described the process like this:

“Smoothing out tiny vellus hairs on the skin requires a totally different approach to removing a large volume of hair, like a beard or mustache. If we were to remove a beard we would have to digitally re-build the actor’s face behind the hair mass. We would need to build a 3D model of the face and then shade the surface of the skin to look realistic. We would then need to track the 3D model to the movement of his head and potentially re-animate his mouth. The amount of lip animation would depend on how much of the original beard occluded his lips. We would need to paint out the parts of the beard that extend beyond his shaven face.”

How long does it take to remove a mustache in post-production?

“Justice League” is expected to hit theaters November 17, slightly over three months away.

Fleet explained the time frame required to build out all the basic elements needed to edit the mustache out: “One week just to make the 3D elements; then another three weeks to track, animate, and render the shaven face; and another two weeks to composite it all together.”

It would take about six weeks to edit a mustache out of a one minute clip, and approximately 25 weeks to edit a mustache out of a five minute clip, according to Fleet.

Unfortunately, Trotman and Fleet were unable to give a good approximation of the costs involved in removing a mustache, as it is hard to calculate or predict without having a better sense of the work required. However, a source who is familiar with this kind of work told Business Insider that it’s unlikely editing out Cavill’s mustache would be a huge cost, since the studio certainly has already 3D modeled his face.