Los Angeles, California - Former Friends star Courteney Cox used a makeup tutorial on Instagram to reveal her biggest tattoo regret, and it's something that you'd never have expected.

Courteney Cox probably didn't expect to be revealing such a big piece of news when she jumped onto Instagram to take viewers through a quick makeup tutorial, but what she came out with was a real doozy.

With the intention of taking people through how to "Get ready with me," Cox talked for a few short minutes about how to be more efficient with makeup.

"Efficient makeup," she captioned the post. "Uploading in a higher quality so you can see my roots."

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In taking fans through her quick routine, she revealed that she not only has tattoos, but that there's one particular inking that she regrets more than anything else.

"My makeup is really simple, and I'll show you how you do it," Cox explains in the video. "First of all, I like to be efficient, so let's put on my moisturizer, which will be this one or this one."

When showing off the Victoria Beckham pencil that she uses, Cox revealed a remarkable secret.

"A long time ago, I tattooed the top of my eyelids – and big mistake!" she said. "It was supposed to be black, but now it's blue. So I always have to wear something to cover that, which is such a drag."

So it turns out that Courteney Cox actually tattooed the top of her eyelids, giving them a permanent blue tinge. Her regret is certainly understandable!

"I just put a line, smudge it, and the same thing over here," Cox explained, before taking her audience through the remainder of her makeup routine.