Former world number one tennis player Ash Barty has revealed she is expecting her first child with husband, Garry Kissick.

Barty announced the news on Instagram on Friday night.

The 26-year-old joked her dog Origi was "already a protective big sister".

"2023 set to be the best year yet. We are so excited for our new adventure," Barty wrote in a caption that included a baby emoji.

Australian tennis players Maddison Inglis and Priscilla Hon were among those to welcome the news on Instagram.

"OMG congrats!!!!," wrote Inglis.

Australian cricketers Aaron Finch and Alex Carey also passed on their best wishes to Barty and Kissick.

"Congratulations to you both!! The best," Finch wrote on Instagram.

Barty shocked the tennis world when she announced her retirement last March.

Her decision came two months after she won the Australian Open women's singles title at Melbourne Park, becoming the first local player to achieve the feat since 1978.

Barty also claimed the 2021 Wimbledon women’s singles crown and the 2019 French Open.

She won 15 career singles title and became world number one in 2019.

Barty was also an accomplished doubles player, winning the 2018 US Open alongside American CoCo Vandeweghe.

She and her long-time partner married in July last year.

AAP/ABC