The organisation's bosses have gifted the rapper with a 44th birthday pass to New York City restaurant Candle 79, and recommendations to healthy and humane eateries in cities where he's performing this month (Dec13).
Humane Society spokeswoman Sue Blackmore tells Wenn, "It a birthday gift and a token of encouragement for moving towards a more humane diet."
Jay Z has taken to his website to detail his new vegan adventure, writing, "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.
"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!"