Naomi Osaka has announced she is expecting her first child, just three days after one of the sport's biggest stars announced she would not be competing at the Australian Open, starting on Monday.

There had been some speculation after her withdrawal that the 25-year-old four-time grand slam winner, who has been open about her work on her mental health, might be pulling the plug on her career.

But the double Australian Open champ revealed plans to be back in action in Melbourne next year.

Japan's Osaka, who has not competed on the WTA Tour since the Pan Pacific Open last September, said on social media, accompanied by what appeared to be a pregnancy scan: "Can't wait to get back on the court but here's a little life update for 2023.

"I know that I have so much to look forward to in the future, one thing I'm looking forward to is for my kid to watch one of my matches and tell someone, 'that's my mom', haha.'"

The news comes five days after another former world number one, retired Australian great and reigning Australian Open champion Ash Barty, also announced she and husband Garry Kissick were expecting their first child.

Osaka, who had not initially elaborated on her withdrawal from the Melbourne grand slam she won in 2019 and 2021, added in her post that she expected to be back at the Australian Open in 2024.

"2023 will be a year that'll be full of lessons for me and I hope I'll see you guys in the start of the next one cause I'll be at Aus 2024," said Osaka, who is also a two-time winner of the US Open, before signing off with the message: "Love you all infinitely".