Serena Williams' daughter ''farts really loud''.

The 36-year-old professional tennis champion and her fiancé Alexis Ohanian welcomed their first child, a daughter named Alexis Olympia Ohanian Jr., last month, and whilst she is relishing in the first weeks of motherhood, she can't help but bemoan the tot's smelly bottom.

On Twitter, Serena wrote: ''I hate to throw my daughter under the bus... but she farts really really really loud (sic)''

The post was accompanied by three crying laughing emojis, and one embarrassed emoji.

Meanwhile, despite having only been a mother for just under two months, Serena is already thinking about getting back out onto the tennis courts, as she says she's always thinking about her ''next victory''.

Speaking before she gave birth, Serena said: ''I am looking forward to becoming a mother and coming back to the courts already. I'm always thinking about what's next: the next victory, the next trophy ... I intend to keep exercising for as long as possible while pregnant.

''I want the baby to be healthy and for that you need a healthy life. Also, when I come back to tennis it'll be better if I've kept as fit as possible all the way through the pregnancy rather than having to lose a lot of weight afterwards in order to get fit again. Eating healthily is a must, but being healthy is a lifestyle.''

The tennis superstar is dedicated to the sport, and recently revealed she even gave her daughter the initials 'AO' in honour of the Australian Open tournament, which she was playing in earlier this year when she discovered she was pregnant.

She shared on Twitter: ''Fun fact my daughters initials are AO as in the Aussie open she won with me @AustralianOpen (sic)''