1. Queens of their domains: 18 #1s and 21 Grand Slams

2. They are two of the most GIFable people on the planet

3. Often imitated, never duplicated.

4. Both give hilariously Diva HSN appearances

5. Well versed in the art of throwing shade

6. Known to have alter egos: Bianca & Taquanda

7. Both love small dogs.

8. Know how to stage a grand comeback.

9. Brett Ratner is a mutual friend.

10. Mariah and Serena once wore the same Roberto Cavalli dress, in different colours and to separate events.