Serena Williams gave birth on September 1 to her daughter, Alexis Olympia Ohanian Jr. and on Thursday, she shared a selfie on her official Instagram account showing her slimmed down physique. Throughout her pregnancy Williams has openly shared her body transformation, first appearing on the cover of Vanity Fair's August issue at the height of her pregnancy. After giving birth, Williams wrote a touching note to her mother, thanking her for helping her embrace her " powerful physique."