Tennis star Serena Williams gave birth to a baby girl on Friday.

News of the birth came just before her sister Venus Williams advanced to the fourth round of the U.S. Open.

Serena and her partner, Reddit co-founder Alexis Ohanian, have yet to confirm the birth but Serena’s coach, Patrick Mouratoglou, tweeted: “I am so happy for you and I feel your emotion.”

He added: “Btw… I wish you a speedy recovery … we have a lot of work ahead of us.”

Celebrities and sports stars have already started giving their congratulations.

 

 

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With files from The Associated Press