Former World No.1 Ashleigh Barty has given birth to a son, Hayden. 

Barty's husband, Australian golfer Garry Kissick, announced Hayden's birth in an Instagram post on Tuesday, saying: "Our beautiful boy ... Welcome to the world, Hayden!"

Barty, 27, and Kissick, her longtime partner, married last July, and the two-time Grand Slam champion announced her pregnancy in January of this year.

"2023 set to be the best year yet," Barty said at the time. We are so excited for our new adventure."

Victoria Azarenka, Carla Suárez Navarro and Johanna Konta, a trio of the Hologic WTA Tour's active and retired, were among the first players to share their well wishes in the comments.

"Congratulations mama!" Azarenka wrote. "All the best to you guys."

The World No.1 for 121 weeks in her career before her retirement last March, Barty won three Grand Slam singles titles: Roland Garros in 2019, Wimbledon in 2021, and the Australian Open last year. Barty's ascent to the top of tennis came after the one-time teenaged prodigy took a 21-month sabbatical from the sport, from 2014 to 2016. 

With her win in Melbourne, Barty famously became the first Australian woman in 44 years to win her home major in singles, since Chris O'Neil in 1978, and fifth in the Open Era. 

“I don’t have the physical drive, the emotional want and everything it takes to challenge yourself at the very top of the level any more," Barty said upon her retirement last year. "I am spent.

"As a person, this is what I want. I want to chase after some other dreams that I’ve always wanted to do.”