The daughter is named after the father, Williams' partner Alexis Ohanian, who co-founded Reddit.
Earlier this month, the world's greatest athlete Serena Williams gave birth to a baby girl.
So far, Alexis has only posted twice but she's already gained more than 28,000 followers.
Serena had introduced her new daughter to the world on last Wednesday.
"You have to check out link in bio for her incredible journey", Williams wrote in the caption".
"It's been a long time", Williams said in the video. On the first two publications of the account, the adorable hairy baby sleeps. The second picture on the account had the baby girl showing off her biceps already in a black and pink onesie with the ideal text "Smart and Strong like my mama".
According to reports in the USA, the new baby girl weighed 6lb 14oz and the entire floor of St Mary's Hospital in West Palm Beach, Florida, was cleared to make way for Serena as a security measure and to help maintain her privacy.