Serena Williams has marked Black Women's Equal Pay Day by writing an article for Fortune calling for fair pay for men and women of all races and colors.
In it, she points out: "Black women are 37 cents behind men in the pay gap - in other words, for every dollar a man makes, black women make 63 cents."
The former World No.1, currently on maternity leave, says that she is financially successful "beyond my imagination" - but adds that had she never picked up a tennis racquet she is well aware of the problems she could be facing.
"The cycles of poverty, discrimination, and sexism are much, much harder to break than the record for Grand Slam titles," she writes.
Williams's article was met with congratulations from the legendary Billie Jean King, herself a long-time champion of equal rights and pay.
Serena later added a tweet of her own - along with a new photo of herself, sporting a top emblazoned with the words "Phenomenal woman," in homage to the poem by Maya Angelou.