The latest celebrity vegans: Jay Z and Beyonce ... at least for 22 days. The couple is going "completely vegan, or as I prefer to call it, plant-based," Jay Z wrote on his blog yesterday, as part of a "spiritual and physical cleanse." They started yesterday (the day before Jay's 44th birthday today) and will go through Christmas. Why now, and why 22 days? "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," the rapper wrote. "It just feels right!" (If this is the type of celebrity story that absolutely infuriates you, we invite you to also read about Gwyneth Paltrow's upcoming lifestyle series.)