World number two Serena Williams is pregnant and due in the autumn, her representative has confirmed.
The 35-year-old had earlier posted a picture of herself on Snapchat posing in a mirror with the message: “20 weeks”, before deleting the post.
The American, who won an Open-era record 23rd Grand Slam in Australia around 12 weeks ago, will miss the rest of the season.
This includes three Grand Slams – the French Open, Wimbledon and US Open.
Williams, who will return to world number one next week, would be eligible to retain her ranking under the WTA special ranking rule if she is ready to play her first tournament within 12 months of giving birth.
US Open Tennis responded to Williams’ message by saying: “Serena Williams will have a new pride and joy to hug and call her own soon! Congratulations on the exciting baby announcement!”
Would it be a 24th Grand Slam in France 2018?
BBC tennis correspondent Russell Fuller:
The news would suggest that Serena won the Australian Open while roughly eight weeks into her pregnancy.
We are very unlikely to see her compete in another Grand Slam before the French Open of 2018. That event will take place four months before her 37th birthday – but do not write off a woman who will return to world number one on Monday.
Victoria Azarenka is a useful guide. Even though she is eight years younger, Azarenka gave birth to her first child in December, returned to serious training in March and is targeting the WTA event in Stanford at the end of July for her return to the WTA Tour.
Best female player of the Open era
Williams, who is engaged to the co-founder of community news and chat site Reddit, Alexis Ohanian, is top of the all-time list of major winners since Grand Slams accepted professional players in 1968.
She is second only to Australian Margaret Court on the list of women’s all-time Grand Slam singles titles leaders.
She is also a five-time Tour finals winner, the last of which came in 2014, and was recently picked as the greatest female tennis player of the Open era by BBC Sport users.