The four-time Grand Slam winner withdrew from the upcoming Australian Open last week.

A reason was not initially provided, but the 25-year-old posted a picture on social media of her baby scan in announcing her pregnancy.

"The past few years have been interesting to say the least, but I find that its (sic) the most challenging times in life that may be the most fun," Osaka wrote.

"These few months away from the sport has really given me a new love and appreciation for the game I've dedicated my life to.

"I realize that life is so short and I don't take any moment for granted, everyday is a new blessing and adventure.

"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 my matches and tell someone, 'that's my mom'."

Osaka added that she expects 2023 to be a year "full of lessons for me", and is targeting a return at the 2024 Australian Open.

She has not played a competitive match since the Toray Pan Pacific Open in Tokyo in September, where she withdrew after complaining of abdominal pain.

The former world number one reached the third round of the Australian Open last year, and lost in the first round at the French Open and US Open.

She missed Wimbledon because of injury.

Osaka, born in Japan to a Haitian-American father and a Japanese mother, has two US Open and two Australian Open titles to her name, and lit the Olympic Cauldron at Tokyo 2020.

She went on to reach the third round of the women's singles tournament at her home Olympics.

Osaka took a mental health break in 2021, and revealed she has been battling depression and anxiety for several years.