Mary-Kate and Ashley Olsen rarely make public appearances these days and don't bother updating others on their lives via social media, but no matter how hard they try to stay private, nothing can stop fans from continuing to obsess over the beloved former child stars and current fashion icons.

We've loved the legendary twins ever since they started rotating shifts as Michelle Tanner on Full House, we watched them solve countless mysteries before dinnertime on The Adventures of Mary-Kate & Ashley, and decades later we still worship classic films like When In Rome and New York Minute. 

Since the Olsen twins have been in the spotlight almost since they came out of the womb, it's hard to believe there's anything we don't know about them. There are plenty of surprising facts about Ashley and Mary-Kate, however, that even their biggest fans either choose to ignore or simply never knew.

20 ASHLEY HAD TO SHARE A SINGLE IDENTITY WITH MARY-KATE AT FIRST

It's adorable when parents dress their twins in identical outfits, but it's fairly problematic when children aren't allowed to develop their own identities. It's bad enough that Mary-Kate and Ashley were constantly forced to dress the same growing up and that they both portrayed a singular character on Full House, but to make matters worse, they were credited as just one little girl on the show.

Early episodes claimed Michelle was played by "Mary-Kate Ashley Olsen," in an attempt to keep people from realizing that the fan-favorite Tanner was being portrayed by twins.

19 MARY-KATE ISN'T ACTUALLY IDENTICAL TO ASHLEY

Mary-Kate and Ashley grew up with different senses of style and they like to dye or cut their hair differently so they don't look exactly the same. It's very surprising that they need to work so hard to be individually recognizable, because believe it or not, they aren't actually identical twins!

They're actually fraternal twins, and Mary-Kate is one inch taller than Ashley and is left-handed, while Ashley is right-handed.

18 ASHLEY'S PARENTS TOTALLY SET HER UP TO STAR IN 'FULLER HOUSE'

We're already on the fifth and final season of Netflix's Fuller House, and there still hasn't been a Michelle Tanner sighting. Danny, Uncle Jessie, Uncle Joey, Aunt Becky and several other classic Full House characters have visited DJ, Stephanie, Kimmy Gibbler and Steve on the sequel series, but Michelle only pops up in vague references now and then.

This is especially depressing because it seems like the Olsen twins' parents always meant for Ashley to star in the show. Her middle name is actually "Fuller"!

17 MARY-KATE IS THE TRUE MICHELLE TANNER

Mary-Kate and Ashley rotated playing Michelle Tanner throughout the entire run of Full House, but in the show's first season, Mary-Kate did the bulk of the work because Ashley cried more when she was put on set for a scene.

The producers eventually wanted to stick with Mary-Kate exclusively for Michelle, but both sisters insisted they keep swapping out on screen.

16 ASHLEY LET FANS THINK SHE MAY RETURN TO ACTING

Fans were devastated when the Olsen twins announced in 2007 that they were done with acting and that if they got involved in movies again, it would only be as producers. Ashley gave everyone hope in 2009, however, when Hamptons Magazine asked if she'd ever return to acting and she responded with "never say never."

She did go on to make brief appearances in the films The Jerk Theory and I'm Still Here, but it seems like hope is now officially lost and the Olsen twins are truly done with acting.

15 MARY-KATE'S FIRST SOLO VENTURE WAS A FAILURE

The first several years of Mary-Kate's acting career found her working next to her twin sister or playing the same role as Ashley, but she finally got the chance to be her own actress in 2006's Factory Girl. Unfortunately, her first solo acting appearance didn't go particularly well, as her one short scene in the film was ultimately cut from its theatrical release and can only be found on the film's DVD.

14 ASHLEY SAID SHE WAS TOO INEXPERIENCED TO BE MICHELLE TANNER

When plans for a Full House reboot started developing, executive producer Bob Boyett contacted the Olsen twins about coming back to portray Michelle. The twins were straight-up with him and quickly turned down the offer. Mary-Kate claimed it was because the timing just wasn't right, but Ashley admitted, "[I haven’t] been in front of a camera since I was 17, and I don’t feel comfortable acting,”

13 MARY-KATE HAS A MORE CONTROVERSIAL SENSE OF STYLE

Mary-Kate and Ashley have taken over the fashion industry over the last several years. They head designer fashion label "The Row," as well as "Elizabeth and James","Olsenboye", and "StyleMint" retail collections. Both stylish sisters frequently find themselves on "best dressed" fashion lists, but Mary-Kate's love for wearing fur has landed her on several "worst dressed" lists as well.

12 ASHLEY WAS THE ACTRESS BEHIND MICHELLE'S MORE SERIOUS STORYLINES

The Olsen twins look far too similar for even the most dedicated fans to recognize which sister is portraying Michelle when, but outside of observing which hand the youngest Tanner sister is using dominantly in a given episode, there's another way to figure out whether Michelle is Mary-Kate or Ashley.

Ashley's mature personality made her the producers' pick for Michelle in particularly emotional or serious scenes.

11 MARY-KATE WAS IN CHARGE OF MICHELLE'S COMEDIC STORYLINES

Most of the adorable Michelle scenes from Full House that made fans laugh featured Mary-Kate. She was the go-to Olsen twin for the show's more comedic moments, and she was also the producers' pick when they needed to access the tomboyish side of Michelle's personality, as that resembled Mary-Kate more than it did Ashley.

10 ASHLEY TRIED (AND FAILED) TO MAKE "THE PERFECT T-SHIRT"

It's not really possible to achieve perfection in the fashion industry, but in 2005, Ashley Olsen co-founded The Row with her sister as a personal project to try to design "the perfect T-Shirt."

Ashley tested her designs on a variety of women of all body shapes and ages in an attempt to find a "commonality in fit and attitude." It's clear that she wasn't quite successful because if the perfect shirt existed, everyone would be wearing it... but Ashley definitely deserves some credit for trying.

9 MARY-KATE KEPT HORSEBACK RIDING AFTER 'HOW THE WEST WAS FUN'

The Olsen twins' roles in How The West Was Fun and It Takes Two forced them to learn how to ride horses at a very young age, and Mary-Kate had so much fun on horseback that she kept with the hobby from then on.

She was a member of the Campbell Hall equestrian team during her time at that school, and she's now a competitive equestrian and even competed at The American Gold Cup in 2016.

8 ASHLEY TRIED SUING THE NATIONAL ENQUIRER

The Olsen twins do their best to keep to themselves and avoid following their own press, but when National Enquirer depicted Ashley as being involved in a drug scandal in 2005, it was too much for her to ignore.

She filed a $40 million lawsuit against the tabloid magazine, causing the National Enquirer to apologize and state that it didn't mean to suggest she was involved in the scandal.

7 MARY-KATE HAS DIFFERENT HEALTH COMPLICATIONS THAN HER SISTER

In 2004, Mary-Kate announced that she suffered from anorexia nervosa and was pursuing treatment to help with her eating disorder. Three years later, she revealed that she was suffering from another health complication and had been hospitalized for a reported kidney infection.

Ashley, meanwhile, suffers from Lyme disease and deal with a lack of energy combined with bad headaches, joint pain, and rashes.

6 ASHLEY IS THE OLDER TWIN

Even though Ashley's name should come before Mary-Kate's alphabetically, everyone refers to the iconic siblings as "Mary-Kate and Ashley Olsen" over "Ashley and Mary-Kate." This has led many fans to believe that Mary-Kate is the older sibling, but the opposite is actually true. Ashley was born two minutes before her twin.

5 MARY-KATE EARNED ONE AWARD THAT SHE DIDN'T HAVE TO SHARE WITH ASHLEY

Since the Olsen twins do everything together, they have to share most of their awards. They shared a star on the Hollywood Walk of Fame, they shared Kids Choice Awards and Young Artist Awards throughout their acting career, and when they became fashion designers, they had to share the title of CFDA Awards' Womenswear Designer of the Year in 2012 and 2015.

Mary-Kate does have one award that her sister doesn't have, though. In 2008, she took home the EDA Special Mention Award for "Most Egregious Age Difference Between the Leading Man and the Love Interest" for her romance with Ben Kingsley in The Wackness.

4 MARY-KATE DOESN'T LIKE WEARING CLOTHES AT HOME

In Mary-Kate's 2007 interview with Harper's Bazaar, she revealed that even though she's a huge fashion icon and makes a living out of designing clothes, she doesn't always love wearing them.

“I run around my house naked with heels all the time,” she admitted. “It’s so funny. All my friends will tell you I love running around in kimonos and jewelry or naked with jewelry.”

3 ASHLEY SAYS SHE EXPERIENCES HER SISTER'S PAIN

Mary-Kate and Ashley don't believe the claims that twins can read each other's minds, but they do actually believe that twins are capable of experiencing each other's pain.

The twins have claimed that at some point during their childhood, one of them was stung by a bee, and that both of them felt the pain. To this day, they still can't remember who was the real victim, because they both feel like they were the one who got stung.

2 MARY-KATE DIDN'T LET GUESTS HAVE CELL PHONES AT HER WEDDING

The Olsen twins' love for privacy has been well-known for decades, but guests at Mary-Kate's wedding to French banker Olivier Sarkozy were still surprised when they were forced to turn in their cell phones ahead of the reception. As Stephanie Tanner would say, 'how rude!"

To make up for this unusual request, attendees were treated to free cocktails and bowls of cigarettes.

1 ASHLEY GETS READY TO GO OUT IN THE DARK

On the rare occasions that the Olsen twins actually make public appearances, they always look utterly flawless. That's why fans will be surprised to learn that Ashley actually chooses to get ready to go out in complete darkness.

"I feel like the worst beauty habit that people have is when they pick their own skin,' Ashley told Elle. 'That's just really bad. Everyone's tempted to do it sometimes, but it's just the worst thing you can do. I prefer to get ready with the lights off so I'm never even tempted to look at my skin!"