It's World Cat Day and we are celebrating these curious creatures by taking a look at their biggest celeb fans. The affinity for felines began around 4,000 years ago when the Ancient Egyptians began domesticating them for pest control. Now they are the beloved best furry friends to many stars. So, who loves them the most? From foster kitty parents Howard Stern and wife Beth Stern to Taylor Swift's Instafamous felines, Meredith Grey and Olivia Benson and more self-proclaimed cat ladies --we take a look.