A popular TikTok video that already has more than 19 million views, has many questioning if they are witnessing an optical illusion, while its creators show the importance of color theory when it comes to choosing the right makeup.

The pair of TikTok stars behind the video, Monica (@makeupbymonicaa) and Jazzi (@jazlmao), have been blowing people’s minds by wearing the exact same lipstick with two very different results. Using Pixi Beauty’s “Evening Rose” shade, the optical illusion lipstick application ends up looking like two completely different hues based on their respective skin tones, according to the New York Post.

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For Jazzi, “Evening Rose” appeared as a dark, reddish color. On Monica, the lipstick appeared bright pink. “It’s color theory,” says the text on top of the video.

@makeupbymonicaa

Reply to @magicmicah69 It looks dark mauve on @jazzi manalo and pale pink on me 🤩 Thank you color theory💯 Lipstick is from @Pixi Beauty shade evening rose ❤️💋#makeuptutorial#liptutorial#makeuptiktok#viralmakeup#beginnermakeup#makeupforwoc

♬ Monkeys Spinning Monkeys – Kevin MacLeod & Kevin The Monkey

For some viewers, the video appeared to be a hoax. “just gonna say we didn’t see the first girl dip it in,” said one commenter. “since the first person did not show where she actually dip the wand. i dunno, feels different shade,” said another.

But after replicating the experiment with no cuts and with the two women clearly dipping their wand into the same bottle, the truth is undeniable. The reason behind it? Simple color theory. This is nothing new for POC makeup enthusiasts — the same makeup can look completely different depending on who wears it.

Color theory refers to the use of the color wheel and color harmonies, in this case in relation to skin tone and makeup shades. When it comes down to choosing a hue, distinguishing one’s skin undertone is the most important step — warm, cool or neutral. From there, the rule of thumb for cool skin types is usually deeper, richer colors, with blue or purple undertones. For warm, vibrant and bold would best compliment skin tone. And for neutral, any color is a possibility.

“This just further proves the need for diverse representation in makeup ads,” reads the top comment. Many more have corroborated the fact that, yes, depending on your skin tone, makeup will appear to be different shades.

TikTok / @makeupbymonicaa

The pair recreated their experiment with brown eye shadow at the request of a commenter, and got a similar result. On Monica, the eye shadow matched her skin tone. But for Jazzi, it looked more like she had a pair of black eyes.

@makeupbymonicaa

Reply to @fatimachaudhary021 its giving barely there on me and a black eye for @jazlmao 🤣 keep them comin!! #eyeshadow#beginnermakeup#viralmakeup#makeuptutorial#makeuphacks#makeuptips

♬ Monkeys Spinning Monkeys – Kevin MacLeod & Kevin The Monkey

They even made another video recreating the initial experiment due to the overwhelming amount of people that still don’t believe their eyes. The only difference this time around was that both women can be seen dipping the wand into the same bottle of lipstick instead of starting the video after the first dip.

“We’re keeping it in frame, we’re not going to have any cuts,” Monica says in the video. Jazzi adds, “We’re just trying to show you that it looks different on different skin tones.”