(CNN) She won a grand slam while pregnant, so it is perhaps no surprise that Serena Williams aims to return to tennis next year and become a grand slam-winning mom.
The tennis great announced Wednesday that she and fiancé Alexis Ohanian are expecting their first child "this fall."
Williams, 35, posted a side profile shot of herself in a yellow swimsuit on Snapchat with a caption that read "20 weeks" before deleting it.
A spokesperson for the tennis player later confirmed the American was pregnant.
If Williams' 20-weeks post was accurate, it would suggest she was about eight weeks pregnant when she won the Australian Open in January.
While Williams will not play again in 2017, meaning she will miss the year's remaining three grand slams -- the French Open, Wimbledon and US Open -- her publicist did say she would return to the tour in 2018.
Williams has not played since winning her 23rd grand slam in Melbourne, withdrawing from the BNP Paribas Open at Indian Wells, California, and the Miami Open citing a knee injury.
Growing celebrity families
"Love & Hip Hop" stars Safaree Samuels and Erica Mena announced in October that they are expecting their first child together. The couple got engaged in December 2018.
Alec Baldwin and wife Hilaria
announced in September that they were pregnant with their fifth child. The couple welcomed their fourth child together, son Romeo, in May. Baldwin has an adult daughter, Ireland Baldwin, from his previous marriage to actress Kim Basinger.
Jenna Dewan and boyfriend Steve Kazee
announced in September that they're expecting their first child together. Dewan shares a daughter, Everly, with ex-husband Channing Tatum.
Rachel Bloom and Dan Gregor are about to get crazier. The married couple who collaborated on her hit series "Crazy Ex-Girlfriend"
went public in September with the news they are expecting their first child.
Singers Matt Pokora and Christina Milian have a new release coming. They
announced in July that they are expecting. It's Milian's first child with boyfriend Pokora, a French singer and songwriter. She has a daughter, Violet, from her marriage to producer-rapper The-Dream.
Former "The Bachelor" contestant Bekah Martinez and her boyfriend Grayston Leonard welcomed their first child together in February.
People reported the baby was a girl.
"Boy Meets World/Girl Meets World" star Danielle Fishel and her executive producer husband Jensen Karp each announced
on their Instagram accounts in January that they are expecting their first child, a boy, in July 2019. Son Adler Lawrence was born four weeks early.
The family of Jionni LaValle, Lorenzo Lavalle, Giovanna LaValle and Nicole "Snooki" Polizzi, shown here in September 2015 in Long Valley, New Jersey, grew. The "Jersey Shore" star gave birth to baby number three, son Angelo, in May 2019.
Richard Gere and his wife, Alejandra Silva shared in a joint production. Silva, 35, shared the news
on her official Instagram account with a picture of her 69-year-old husband and the Dalai Lama touching her belly. Son Alexander was born in February. The couple each have a child from previous marriages.
Carrie Underwood
announced in August that she and husband Mike Fisher were expecting their second child. They welcomed son Jacob Bryan Fisher on January 21.The pair are the parents of 4-year-old Isaiah Michael. The singer said her pregnancy would delay her new concert tour until 2019.
Author/musician Leafar Seyer and wife, TV personality Kat Von D (seen here pregnant in September 2018) introduced their son, Leafar Von D Reyes, in December 2018. It's the first child for the couple who married in February.
'Baby GOAT'
Williams, who is second only to Margaret Court on the list of women's all-time grand slam singles titles, has received congratulatory messages from around the world.
Former world No.1 Andy Roddick tweeted: "There's gonna be a baby GOAT... We are so happy and we know @serenawilliams will be a great mother."
Christ Evert, 18-time grand slam winner, said it was a "very special year ahead" for Williams.
Steve Simon, Women's Tennis Association (WTA) chief executive, said: "We're excited for Serena. This is wonderful news and we wish her the very best. We'll look forward to seeing her when she's back competing again."
Williams will not be the first player to return to the tennis tour after giving birth.
Belgium's Kim Clijsters triumphed at the US Open in 2009 to become only the third mother to win a grand slam, following in the footsteps of fellow tennis moms Court and Evonne Goolagong.
Former world No.1 Victoria Azarenka is also set to make her comeback in July after giving birth to her first child in December.
Mommy duty! In the park with my son! Recharging 🔋for a great week of work! 💪🏻 #sundayfunday #beatifulday #familytime #familylove #blessed #KingLeo #lovemyboy
Williams' latest news comes after she surprised fans in December by announcing her engagement to Ohanian, Reddit's co-founder. The pair had kept their romance out of the spotlight.
Serena Williams engaged to Reddit co-founder Alexis Ohanian
She had alerted the world of her impending nuptials on Reddit, with tech entrepreneur Ohanian posting on his Facebook page, linking to her Reddit post and adding: "She said yes."
CNN's Laurie Segall, Jill Martin and Aimee Lewis contributed to this report