28 Facts That You Forgot About Mary-Kate and Ashley Olsen What better way to celebrate nearly three decades of Mary-Kate and Ashley?

June 13, 2014 -- intro: Happy birthday, Mary-Kate and Ashley Olsen! Today, our favorite twins turned 28. To celebrate, we took a trip down memory lane and counted down 28 facts about the famous fraternal faces that you may not know.

quicklist: 1 title: 1. They've Already Had Dentures text: Because they lost their baby teeth at different rates, the duo had to be fitted with fake teeth to play a toothy Michelle Tanner on "Full House." media: 24130722

quicklist: 2 title: 2. They Were Pint-Sized Producers text: The twins became the youngest Hollywood producers in 1992. They were 6.

quicklist: 3 title: 3. The National Academy of Television Arts and Sciences Could Tell Them Apart text: While both have since retired from acting, one has enjoyed more critical acclaim than her twin sister. Mary-Kate's work in "So Little Time" was nominated for a Daytime Emmy. Ashley's performance was not so well received.

quicklist: 4 title: 4. Mary-Kate Has a Running Habit text: But she doesn't bother with spandex or sneakers. Instead, she slips into her birthday suit and a pair of stilettos. "I run around my house naked with heels all the time," Mary-Kate told Harper's Bazaar in 2007. "It's so funny. All my friends will tell you I love running around in kimonos and jewelry or naked with jewelry." Stars, they're just like us!

quicklist: 5 title: 5. Jimmy Fallon and Will Forte Took Them to a Prom text: ... Well, sort of. Mary-Kate and Ashley missed the high school dance to co-host "Saturday Night Live" in 2004. Fallon and Forte graciously served as their dates in a prom-themed sketch.

quicklist: 6 title: 6. They Recognize Their Weaknesses text: Appearing with Mary-Kate on "Ellen" in April 2014, Ashley admitted: "I don't think we're very good singers." That seems like an unfair characterization. We think "Brothers for Sale" was a very strong album.

quicklist: 7 title: 7. A Lot of Creepy Men Celebrated Their 18th Birthday text: Several websites launched countdown clocks to mark that milestone birthday and the fact that the twins came of age. It was as uncomfortable as it sounds.

quicklist: 8 title: 8. Mary-Kate Is Still Mastering Basic Grooming text: "You know, the truth is I feel like I just learned how to brush my hair like last week," Mary-Kate told Marie Claire in March 2014. See that? Our mother was right after all. You're never too old to learn!

quicklist: 9 title: 9. The Scent of Coffee Gives Mary-Kate 'the Warm and Fuzzies' text: In the same Marie Claire interview, Mary-Kate spoke lovingly of the brew: "It feels like a part of my childhood. It was something that I smelled a lot. It just reminds me of having a routine in the morning."

quicklist: 10 title: 10. They're Fraternal text: Ash is an inch shorter than her sister and has a faint freckle above her upper lip. Mary-Kate has wider eyes and thinner lips than her two-minute-older twin.

quicklist: 11 title: 11. Mary-Kate Will Be a 'Cool' Mom text: She was spotted smoking alongside her fiance, Olivier Sarkozy, and his daughter. Just kidding. Very uncool, Mary-Kate. Smoking kills. media: 24130587

quicklist: 12 title: 12. Our Lips Are Sealed text: On their "Ellen" appearance earlier this year, Ashley contended that she had her first kiss before her twin sister. Mary-Kate disputed the claim. Ellen did not inquire further.

quicklist: 13 title: 13. They Were Friends with a Pretty Little Liar text: "Pretty Little Liars" actress Troian Bellisario grew up across the street from the Olsens. They lost touch after the duo moved away, but Bellisario went on to play a small part in the straight-to-video movie, "Billboard Dad."

quicklist: 14 title: 14. Move-In Ready text: Mary-Kate and Ashley Olsen sold a $7.3 million Manhattan penthouse apartment in 2005 that they never lived in. We understand. Six thousand square feet and natural light just isn't for everyone.

quicklist: 15 title: 15. The Write Stuff text: Mary-Kate is left-handed. Ashley is right-handed. Michelle Tanner was thus, necessarily, ambidextrous.

quicklist: 16 title: 16. They Were Not Always Individuals text: No, really. "Full House" producers credited the twins as "Mary-Kate Ashley Olsen" in early seasons of the television show. They apparently did not want people to know that the role of Michelle Tanner was played by twins.

quicklist: 17 title: 17. Ashley Has a Better Memory text: On Bravo's "Watch What Happens Live," Elizabeth Olsen told a fan that Mary-Kate forgot her birthday this year. Lizzie assured listeners that she would not hold the slip-up against her sister. "She was out of town!" the younger Olsen reasoned.

quicklist: 18 title: 18. Diaper Duty text: Bob Saget took his role as their on-screen father seriously. In "Dirty Daddy: The Chronicles of a Family Man Turned Filthy Comedian," Saget recalled changing the twins' diapers on set. media: 24130666

quicklist: 19 title: 19. They Were Trend Setters text: Mary-Kate and Ashley were the first twins to share a star on the Hollywood Walk of Fame.

quicklist: 20 title: 20. They Founded a Fashion Line to Find the Perfect T-Shirt text: The twins co-founded luxury label The Row in order to craft a superlative t-shirt. Mary-Kate told The Wall Street Journal that she and her sister decided to launch the brand in response to the question: "How we could make a perfect T-shirt in a great fabric that would fit any age." media: 24130538

quicklist: 21 title: 21. They're Big in Norway text: The twins launched a collection with Norwegian retailer Bik Bok in 2013.

quicklist: 22 title: 22. It's Kind of Like a Pool Party text: The Row's first standalone store on Melrose Place is outfitted with a full-size courtyard pool. The flagship reportedly keeps towels on hand for shoppers looking to cool off.

quicklist: 23 title: 23. Mary-Kate Sparkles text: Olivier Sarkozy proposed to the younger twin with an $81,000 vintage Cartier engagement ring.

quicklist: 24 title: 24. They Have a Brother text: Sister Elizabeth is now famous in her own right, but the twins also have a brother. Trent is a year older than the twins and reportedly toyed with the idea of getting into acting. A childhood friend told the New York Post that the "prankster" sold his sisters' autographed pictures for pocket change in elementary school. Clearly, entrepreneurship runs in the family.

quicklist: 25 title: 25. Ashley Has a Back-Up Plan text: A friend asked Ashley to chop off several inches of her hair this year. Of her skills, Ashley boasted: "She made me do it, but it looks great."

quicklist: 26 title: 26. Ashley Has a Middle Name text: It's "Fuller." Doesn't have quite the same ring to it as "Kate," does it?

quicklist: 27 title: 27. They're as Close as Ever text: In December 2013, Ashley told Allure that their twin bond is "beyond words." #Aw. media: 24130455

quicklist: 28 title: 28. Matchy-Matchy text: They may be all grown up, but it's never too late to coordinate on the red carpet. The duo donned matching black dresses to attend this year's C.F.D.A. Awards in New York City.