Happy birthday, Michael Jackson! Today, August 29, would have marked the 53rd birthday of the 'Thriller' pop icon. Jackson's life and music career came to a tragic end when the entertainer died two years ago due to a drug overdose. However, his legacy and influence will never be forgotten, as pop stars like Usher, Jennifer Hudson, Big Boi, Cody Simpson and Ciara exhibited by extending birthday wishes to the late great King of Pop. See what your favorite stars were chirping about today!