The tennis star revealed on Thursday that her boyfriend of almost two years, Reddit co-founder Alexis Ohanian, popped the question after whisking her away on a surprise trip to Rome.
Williams, 35, shared the news on Reddit by posting a poem, writing: 'At the same table we first met by chance / This time he made it not by chance / But by choice / Down on one knee / He said 4 words / And I said yes.'
Ohanian, 33, later posted Williams' poem to his Facebook account, writing: 'She said yes.' He also commented on her poem on Reddit, writing: 'And you made me the happiest man on the planet.'
Williams revealed in her poem that she came home to find her bags packed and ready to go for the surprise trip that Ohanian had planned for them.
'Someone had a bag packed for me / And a carriage awaited / Destination: Rome / To escort me to my very own "charming" / Back to where our stars first collided,' wrote Williams.
She also included a graphic that showed her dressed in her tennis gear and floating on air as Ohanian presented her with a large diamond.
Williams, who is notoriously private about her personal life, has never spoken about her relationship with Ohanian in the press.
The pair were however spotted at dinner in San Francisco back in 2015 thanks to surveillance video that was later released by the restaurant.
During that date, a man stole Williams phone off the table and then rushed out of the restaurant.
Once Williams noticed what had happened she quickly got up, made her way through the crowd, and caught up with the man outside.
In the end, the man sheepishly returned the device and Williams returned to her meal.
There will be little time for celebration however as Williams is due back on the court next week, as she is set to play in the ASB Classic in Auckland, New Zealand.
It will be her first tournament since the US Open this past September, with Williams opting to cut her season short following her defeat in the semifinals.