The club of WTA moms grew by one on Sunday, as former World No.1 Ana Ivanovic announced the birth of her first child, a son, with husband Bastian Schweinsteiger on social media.

"Welcome to the world our little boy," Ivanovic wrote in posts on Twitter and Instagram. "Words can not describe the joy and the happiness we feel in our hearts!"

Later, Schweinsteiger also confirmed the news on his social media accounts.

"Welcome to the world our little boy! We are so happy," the soccer star tweeted.

The 2008 French Open champion announced her retirement from tennis in December of 2016, after winning 14 WTA titles in her career. Ivanovic was ranked World No.1 for a total of 12 weeks in 2008, and was honored in a retirement ceremony on Court Philippe Chatrier at last year's French Open.

Among the first players to offer their congratulations to the new parents were Garbiñe Muguruza, Elena Vesnina, Naomi Broady and Jarmila Wolfe.

Ivanovic and Schweinsteiger, a German soccer player who plays as a midfielder for Major League Soccer club Chicago Fire in the United States, were married in July of 2016 and Ivanovic announced her pregnancy in November.