Former world number one tennis player Osaka Naomi has announced she is expecting her first child, just days after she pulled out of this month's Australian Open.

Osaka broke the news on Wednesday on Twitter in English and Japanese accompanied by an image of a sonogram.

She tweeted, "Everyday is a new blessing and adventure," and "one thing I'm looking forward to is for my kid to watch one of my matches and tell someone, 'that's my mom.'"

Osaka went on to say she hopes to see her fans at the start of next year because she'll be at the 2024 Australian Open. She concluded the post by saying, "Love you all infinitely."

Osaka, 25, hasn't competed in world tour events since taking part in one held in Tokyo last September.

She has won four Grand Slam tournaments and is currently ranked 47th in the world.