When behind closed doors, we all do embarrassing things like dance around in our underwear, wear dirty clothes, and even pick our nose. But we don't tell anyone about it! It's actually shocking how many celebs openly admit to doing disgusting things. Whether it's forgoing oral hygiene, farting in public, or refusing to bathe, we really wish these celebs never told us about their filthy habits.

While these stars disgust us with their nasty confessions, we have to admit that it takes some guts to be themselves, as embarrassing as it may be. Stars like Cameron Diaz and Matthew McConaughey stand behind their personal hygiene habits and have built a whole lifestyle around it. Even if they have a reputation of smelling like a bunch of dirty hippies.

We've compiled a list of 15 celebs that have publicly confessed to some truly shocking filthy personal hygiene habits. Proceed with caution: This list may cause you to lose your appetite and frankly, some respect.

Jessica Simpson Doesn't Like To Brush Her Teeth

Whether she was asking if Chicken of the Sea was made of tuna or fish, or inquiring about the age-old question of whether or not buffalo wings are actually comprised of buffalo, Jessica Simpson's mouth gets her in a lot of trouble. But the pop-star made it to this list because she has openly admitted to not brushing her teeth. Back in 2010, Jessica confessed her filthy hygiene habit on the Ellen show. She told the audience that she brushes her teeth "maybe three times a week." Woah!

Most dentists recommend that a person should brush his/her teeth twice a day, along with daily flossing and yearly trips to the dentist. Suddenly, we're realizing that we're actually glad we've never had the chance to kiss the beautiful Jessica Simpson.

Snooki's Kitty Litter Facials

MTV's Jersey Shore gifted us with some bat-sh** crazy reality stars, but no one could hold a candle to its true break out star, Snooki, or Nicole Polizzi. Whether she was going to bed in her dirty outdoor slippers or getting drunk and sweaty on the beach before noon, Snooki never failed to shock us with her icky behavior. But nothing could have prepared us for what she said on Conan O'Brien's late night show. She admitted to using cat litter to exfoliate her skin. The reality star said that she uses it because it's a cheap alternative to expensive spa treatments. Snooki explained, "So I Googled what else I could use that's, like, not so expensive, and it was cat litter!" Let's pray the litter is fresh out of the bag and not the litter box.

Baby-Wipin' Brad Pitt

Word around Hollywood says Brad Pitt stinks—no, not his acting—but his actual body. Apparently, while filming the movie Inglourious Basterds, Brad gave some of his co-stars some of his genius hygiene tips. According to co-star and friend Eli Roth, Brad told him that if he didn't have time to shower, baby wipes would be a great alternative. Roth said, "He shared that when you’re sweating and don’t have time to take a shower, you just take a baby wipe and rub it under your armpits." He even earned the name "Arm Pit" on the set of Troy due to his righteous stank.

While Brad Pitt may be a whiz when it comes to performing in front of the camera, he definitely doesn't understand why soap is the best option when it comes to fighting body odor. It's also rumored that ex-wife Angelina Jolie also became rip from time to time. Perhaps she taught him the baby wipe trick?

Anderson Cooper Never Washes His Nasty Jeans

Look, we all hate when our favorite jeans fade from many cycles in the washing machine, but that doesn't mean we should refrain from ever cleaning them, does it? Believe it or not, successful journalist and news anchor, Anderson Cooper has openly admitted to washing his jeans maybe four times a year. And when he does wash them, he just wears them into the shower. What?! What about the time the air-conditioning broke in the news studio or the time (okay, many times) Kathy Griffin made him uncomfortable on the CNN New Year's Eve Special? Nope, apparently no amount of crotch sweat can force Anderson to pop those bad boys into the wash.

Anderson confessed his dirty jean secret on his show Anderson Live with TLC's What Not To Wear's Stacy London. Anderson claimed, "So the times I've washed my jeans, maybe twice in six months... I've worn them and walked into my shower with them and put some soap on them and then air dried them...Isn't that how you are supposed to do it?" No, Anderson. No it's not.

Jennifer Lawrence Pees In Sinks

For most people, washing their hands in the bathroom sink is the last step in the process of "doing their business." But not for the Oscar-winning actress, Jennifer Lawrence. In an interview on MTV, alongside her Mockingjay co-stars, the actress admitted to oftentimes peeing in the sink when going in the bathroom with girlfriends. She literally said, "I’ve peed in some sinks. When two girls go into a bathroom, someone’s gotta take a sink. I actually like taking the sink." She also confessed that she usually doesn't wash her hands after using the toilet. While many of us were shocked at this news, it's actually been reported that nearly half of people fail to wash their hands after a typical trip to the bathroom. Ick!

The Flatulent Katy Perry

Katy Perry is known for having a strong stage presence, but is she a little too present? The larger-than-life pop star confessed to farting while performing for thousands of people in an interview with musician, Florence Welch. Katy was explaining how she has to pee a ton before going on stage, which led to her candid confession about how she farts on stage. Katy said, "I've farted on stage. It's horrible, I can't believe I just said that. It's my stage! I'm hopping around, I'm a little gassy." Well Katy, maybe you should try skipping out on the burritos before heading out on stage.

Kesha Puts Strange Men's Beards In Her Mouth

Kesha has always been a bit of a wild card, and we're not surprised that she welcomes filthy things in and around her mouth. Kesha has openly admitted she enjoys putting men's beards into her mouth. Why, you ask? We really wish we had an answer, but we're as confused and grossed out as you are. Kesha is so into sucking on chin hair that she started a Tumblr entitled, "Putyourbeardinmymouth."

While Kesha may think sucking on beards is all fun and games, she ought to know that beards are a complete cesspool for bacteria. Between sweat, germs, and bacteria from food, beards are full of crap you really don't want to be putting in your mouth. We strongly suggest that Kesha head to the doctor and get checked for...well, everything.

Megan Fox Hates Flushing The Toilet

Megan Fox may be smokin' hot, but once you learn about some her of disgusting habits, you may change your tune. Megan has spoken openly about her filthy lifestyle and almost seems proud of it. Megan confessed in an interview that she's awful to live with because she's so dirty. Megan even said, "I’m horrible to live with. I don’t clean. My clothes end up wherever I take them off. I forget to flush the toilet. Friends will tell me, 'Megan, you totally pinched a loaf in my toilet and didn’t flush.'" Imagining Megan Fox leaving a nasty dump to stew in the toilet is probably the most unattractive thing ever. Why doesn't she just flush the toilet? Is she that lazy? If she is lazy enough to not want to flush a toilet, we can only imagine the kind of filthy home she keeps.

Robert Pattinson Doesn't Wash His Hair

Robert Pattinson is lucky that he has nice eyes and an accent to distract us from noticing his greasy, nasty hair. Twilight star, Robert Pattinson has openly admitted to not caring about washing his hair and doesn't really see the need for it. In an interview with Extra, Robert responded to a rumor going around about him not washing his hair for six months. Robert's response? He said, "Probably. I don't know. I don't really see the point in washing your hair." Well, that answers that.

If Robert doesn't wash his hair, what else isn't he washing? Knowing about his greasy hair leads us to believe he probably stinks. Is that why Kristen Stewart cheated on him a while back? We wouldn't be surprised.

Joan Rivers Never Washed Her Clothes

The late comedian, Joan Rivers was always giving fashion advice. She used to judge the stars on countless red carpets and on her show, Fashion Police. But when it comes to cleaning, maybe Joan didn't give the best advice. Joan has admitted to spraying her costumes with a special concoction consisting of vodka and water. She even confessed to spraying her arm pits with the vodka spray, saying, "I always spray my costumes with vodka and water. It's an old Broadway trick—two-thirds water and one-third vodka—spray your armpits and you'll never smell again." Did this spray really work? Or did Joan carry around her own brand of musk? Sure, her vodka spray may be an old Broadway trick, but we think for now we'll stick with our trusty Tide.

Olivia Munn Rips Out Her Eyelashes

Olivia Munn suffers from an obsessive compulsive disorder called Trichotillomania. The disorder often makes her rip out her eyelashes forcefully. We can't help but cringe when we think about it. Olivia explained in an interview, "It doesn’t hurt, but it’s really annoying. Every time I run out of the house, I have to stop and pick up a whole set of fake eyelashes." While Olivia says she doesn't have other common symptoms of the disorder like biting her nails, who knows what other hair of hers she rips up.

Cameron Diaz Is Anti-Anti-Perspirant

A-list actress Cameron Diaz recently made a somewhat shocking confession about her personal hygiene habits. Cameron has no time for deodorant and hasn't used the stuff for 20 years! She claims that everyone should give up anti-perspirant due to its supposed harmful long-term effects on the body. She also says men should stop using deodorant, and trim their armpit hair so that the scent doesn't stick around. Ew! Cameron is all about going all natural as we learned in her book, The Body Book. The actress believes women should let their hair down there grow au naturale and listen to their bodies. Even if Cameron is on to something health-wise, we can't help but be grossed out by her candid claims.

Matthew McConaughey Is Afraid Of Deodorant

Actor Matthew McConaughey epitomizes the idea of manliness. So it's not super surprising that he takes pride in "smelling like a real man." Many of his co-stars, including Kate Hudson, have complained about his strong body odor and have begged him to wear deodorant. But Matthew never budges and said at one time, "Your natural smell smells, one, like a man, and, two, smells like you." He apparently believes deodorant makes you smell like someone else who's not you, and that's super creepy. We don't care who you smell like as long as it doesn't make us want to upchuck our lunch.

Shailene Woodley Eats Snacks Made Of Clay

Shailene Woodley is a great actress and is getting a lot of attention these days for her work as well as her activism. But what really turned heads was when she admitted to eating clay on Letterman back in 2014. Shailene confessed to eating about a teaspoon of clay a day and usually brushes her teeth with it. Can you imagine rubbing clay on your teeth every night?!

Shailene stands behind the idea that clay has some sort of nutrient-rich element since people have been eating it in different cultures for hundreds of years. But just because people have been doing it for a long time, doesn't mean it's a good idea. Shailene also claimed that pregnant women in many different cultures benefit from eating clay. Brings a whole new meaning to the saying 'sh**ing bricks', doesn't it?

Catherine Zeta Jones Doesn't Know How Food Works

Catherine Zeta Jones may be beautiful and talented, but is her brain wired a little wrongly? The actress has openly admitted to brushing her teeth with just about anything but a tube of toothpaste. Catherine says that after meals, apples are a great way to cleanse her mouth and clean her teeth. And if she doesn't have any apples around, she actually uses strawberries because, who doesn't use strawberries to brush their teeth?! Catherine claims, "The juice or pulp of strawberries contains malic acid which serves as an astringent and can lighten surface stains."

But she doesn't stop there. The actress also uses beer as shampoo! Catherine conditions her hair with both honey and shampoo even though she says she stinks afterward. Someone needs to teach this woman about food and how eating works.