He’ll still have plenty of “cheddar,” but Jay Z is going vegan.

For 22 days, that is. The rapper, who celebrates his 44th birthday Wednesday, announced on his lifestyle Web site that he has taken on a challenge to eat “completely vegan.”  He added that his wife, Beyoncé, would join him for what he called a “spiritual and physical cleanse.”

Jay Z explained that the 22 days coincided with the number of days until Christmas. The post also noted that the digits add up to four — a significant number for the couple who both have birthdays on the 4th (Beyoncé’s birthday is September 4). They married on April 4, 2008 and even have the roman number IV tattooed on their ring fingers.

Jay Z joins a host of other notables who have pledged to remove animal products from their diet. Former vice president Al Gore recently went vegan and Bill Clinton has been vegan for several years. Longtime vegan and hip-hop mogul Russel Simmons tweeted Jay Z’s announcement, adding “welcome to the club, Jay and Bey.”

Jay Z may have been inspired by a celebrity friend. “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,” he wrote. Vulture joked that actress, GOOP founder and friend-of-the Carters Gwyneth Paltrow may have inspired the decision. For the record: Paltrow is well-known for her health conscious diet, which includes many vegan recipes, but she’s not (always) a vegetarian.

The rapper promised to post updates and asked for restaurant recommendations. Fans obliged in the comments suggesting high-end vegan restaurants in and around New York City. Others said they hoped the challenge would be permanent, an idea to which Jay Z seems open.

“I don’t know what happens after Christmas,” he wrote. “A semi-vegan, a full plant-based diet? Or just a spiritual and physical challenge? We’ll see…”

One idea: A Jay-Z remix to Dead Prez’s “Be Healthy,” a track that espouses the benefits of a vegan diet (warning: it also contains some NSFW lyrics).