8 Beauty Rules That Princess Diana Swore By

"[Princess Diana] realized the power of hair and makeup, and that is something that should never be underestimated–by anyone," her makeup artist Mary Greenwell once said (opens in new tab).

Just as beautiful on the outside as she was on the inside, everything she did–from chopping off her dirty blonde hair to wearing blue eyeliner–garnered international attention. On her wedding day alone, 17 million viewers from around the world tuned into the ceremony.

And while a natural beauty through and through, she still had some tricks up her sleeve. Here, find a few beauty rules Princess Di lived by.

1. Follow a proper skincare routine. "She had the most incredible skin, which frankly at the end of the day also can come down to family genes," said Greenwell in an interview with (opens in new tab)Stylist (opens in new tab). However, The Queen of Hearts never took it for granted–cleansing, toning, moisturizing, and applying serums/SPF daily.

2. Always get enough sleep. Quality sleep was a matter-of-fact part of Princess Diana's beauty routine. And it's no wonder why...

"Lack of sleep causes the skin to look pale and tired because the circulation has been impaired," explains celebrity esthetician Renée Rouleau (opens in new tab). "In addition, it's important to get a good night's sleep because sleep deprivation also causes stress, which can aggravate all skin conditions. Bottom line: When you're tired, you look it!"

3. Do everything in moderation. "After I started working with her, Diana did everything in moderation," she said. "She cut back on drinking so her skin was 100 percent. If you smoke, drink or do anything to excess, you will destroy your most important beauty asset–your skin."

4. Have a signature makeup look. "We always started with a moisturizer, a foundation to suit her skin tone exactly, and then used a concealer to lift the eye area," noted Greenwell. "Mascara–which is a gift of all gifts–and lip color to suit her mood that day."

5. Never wear eyeliner that matches your natural eye color. Princess Di often wore blue eyeliner. Or, at least she did before meeting Greenwell. "Blue eyes should never wear blue pencil or shadow–it dulls your eyes!" she says.

6. Apply mascara from the roots up. "I always taught her to make sure–when applying mascara by herself–that she covered the roots of the lashes too," she explains.

7. Never leave the house without misting on fragrance. "She always, always, always wore fragrance, which is a huge thing in a woman's life," says Greenwell. "It's kind of the final touch of beauty, walking out smelling divine and chic and individual."

8. Take risks with your hair. In 1990, on set with Vogue and photographer Patrick Demarchelier, Princess Di asked hairstylist Sam McKnight to do the unthinkable (opens in new tab)–cut off all of her hair. In stark contrast to the long and voluminous hair of the '80s, her style was a "sportier, more androgynous look." And guess what? It's how we envision her to this day.

Follow Marie Claire on Instagram (opens in new tab) for the latest celeb news, pretty pics, funny stuff, and an insider POV.