The 44-year-old rapper and his pop star wife are inspired by a close friend to give up meat and dairy products, reported E! online.
"Psychologists have said it takes 21 days to make or break a habit. On the 22nd day, you've found the way. On December 3, 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," Jay Z wrote on his blog.
"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 said.