Jay-Z and Beyonce have pledged to go vegan.

The pair are taking the 22Days Challenge, which is an initiative promoted by Jay Z's exercise physiologist friend Marco Borges, which aims to change people's dietary and exercise habits by encouraging them to go vegan for 22 days.

Writing on his blog, Jay Z put: "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!! 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 continued: "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…"