Beyonce's been known to engage in her fair share of fad and a tad bit extreme diets: She lost 20 pounds for her role in "Dreamgirls" by going on a Master Cleanse and adopted a protein-rich diet post-pregnancy, which allowed her to lose 60 pounds. For her next feat, Bey is joining husband Jay Z in a 22-day challenge of going vegan.

Jay Z posted the following explanation to his website yesterday, relating the experiment to his 44th birthday:

Psychologists have said it takes 21 days to make or break a habit. On the 22nd day, you’ve found the way.

On December 3rd, one day before my 44th birthday I will embark on a 22 Days challenge to go completely vegan, or as I prefer to call it, plant-based!! This all began a few months back when a good friend and vegan challenged me to embrace a “plant-based breakfast” everyday. It was surprisingly easier on me than I thought…

Why now? There’s something spiritual to me about it being my 44th birthday and the serendipity behind the number of days in this challenge; 22 (2+2=4) coupled with the fact that the challenge ends on Christmas day … It just feels right!

So you can call it a spiritual and physical cleanse. I will post my progress … Any professional vegans out there that have any great food spots please help out! Please ha. I don’t know what happens after Christmas. A semi-vegan, a full plant-based diet? Or just a spiritual and physical challenge? We’ll see…

Best of luck and health!

P.S. B is also joining me.

The website Jay then references, 22 Days Nutrition, explains that "foods made of the best ingredients should satisfy not only the body, but also the spirit. We believe that the right attitude and approach to healthy living can positively affect the world."

This might prove difficult for the couple, who likes to indulge in the occasional burger, pizza and wine. Nevertheless, we wish them luck. Post updates, you guys! And happy birthday, Jay!

Also on HuffPost:

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  • Christina Aguilera

    The songstress used to live her life by the 7-Day Color Diet. That means she ate only foods of one color every day, starting with white, then red, green, orange, purple, yellow and finally all of the colors combined.

  • Victoria Beckham

    Posh spice swears by the Alkaline Diet which revolves around the pH levels, or acidity, of the body and its fluids (urine and blood). On Alkaline, 70 percent of all food should be raw, cow dairy shouldn't be consumed, and protein should be eaten in moderation.

  • Jennifer Aniston

    The bride-to-be confessed in recent years that she's given up fad dieting for a healthier, more maintainable lifestyle. But before that, Aniston swore by baby food and a diet based on coconut oil, which is supposed to boost metabolism and help lose weight quickly.

  • Megan Fox

    The "Transformers" actress used to practice the Vinegar Diet -- straight-up shots of vinegar which supposedly cleanse out the stomach and its content.

  • Kim Kardashian

    The reality star has spoken openly about the different diets she dabbled in to keep her sexy curves. She admittedly tried the Atkins Diet, macrobiotic eating, eliminated all gluten, sugar and dairy from her diet at some point, and even tried the cabbage-soup diet (basically eating cabbage soup very day). She also endorses the weight loss system QuickTrim.

  • Gerard Butler

    Butler is a yo-yo dieter and has once said that to go from "300" buff to "The Ugly Truth" soft, he binges on food then cleanses to undo the damage. He blamed his less-than-healthy eating habits on abstaining from smoking and drinking.

  • Denise Richards

    Charlie Sheen's ex was reportedly swept up in The Cookie Diet craze back in the day. It consists of six cookies and one low-calorie dinner of lean meat and vegetables each day, for a total of 1,000 daily cals.

  • Jennifer Lopez

    J. Lo used to follow the Dukan Diet plan, a four-step diet which is similar to Atkins in that it focuses on protein above all else. She was also said to carry around grapefruit extract in pill form to kickstart her metabolism.

  • Beyonce

    Queen Bey's Master Cleanse became the talk of the town when it helped her drop 20 pounds for her role in "Dreamgirls." Her diet consisted of nothing but lemon juice, maple syrup and cayenne pepper.

  • Gwyneth Paltrow

    Prior to her new book coming out, Paltrow used to frequently talk about her regimen which consisted of fasting, cleansing and detoxing (somehow, all three are not the same). She used GOOP to make her methods known, including the Master Cleanse which she later called "hallucinogenic," and her suggestions for cleaning out one's bowels ("half a cup of castor oil or a mild herbal laxative.")

  • Amanda Seyfried

    The "Les Mis" star admitted to working out like crazy to keep her figure and periodically doing a raw food cleanse, which means eating only spinach for lunch.

  • Fergie

    The preggers singer once said she attempts to trick herself out of eating by telling herself french fries are poison, and allowing herself only one bite of dessert.

  • Jennie Garth

    Forever Kelly said she used to cleanse once every two years with TrimFit cleanse, which allows one meal a day. Her ex-husband Peter Facinelli used to "suffer" through it with her.

  • Giuliana Rancic

    The TV host was linked to two fad diets: The Ultimate Tea Diet, which had her drinking multiple cups of tea each day for 14 days in addition to eating three light meals; and a detox diet from Paltrow's guru, who put her on a three week regimen of smoothies plus one daily meal of raw veggies.

  • Simon Cowell

    Cowell lost weight by consuming only veggie smoothies plus a small protein meal for dinner.

  • Leona Lewis

    Leona kickstarted her dramatic weight loss a couple of years ago with a strict, month-long detox, subsisting on nothing but vegetables and water.

  • Whitney Port

    5'9" Whitney said she gained 25 pounds in college but has since slimmed down to 115 by working out and avoiding carbs, sugar and fried food.