The five-time grand slam winner confirmed that she and British art dealer Alexander Gilkes were getting hitched, sparking a flood of congratulatory messages on social media.
Gilkes is a known close friend of Prince William, whom he attended Eton College with.
The British businessman – who has a reported net worth of $20 million – is also the ex-husband of Meghan Markle’s best friend Misha Nonoo.
Sharapova shared the momentous news on her Instagram page, where she has more than four million followers.
“I said yes from the first day we met❤️This was our little secret, wasn’t it 💍🥂@gilkesa,” the 33-year-old wrote alongside a picture of the happy couple on Instagram.
The Russian tennis great’s message received more than 180,000 likes within the first few hours of it being posted.
Fans from all around the world offered their congratulations to Sharapova and her new fiancee.
“Ahhhhh yessss congratulations!!! 💖💖💖💖💖💖💖💖💖💖💖💖,” actress Lily Collins wrote under Sharapova’s post.
Sports broadcaster Erin Andrews also told Sharapova “congrats” on the engagement, with messages flooding in from around the world for the loved-up couple.
Sharapova’s fiancee over the moon
Gilkes also took to Instagram to share his excitement about the engagement to Sharapova.
“Thank you for making me a very very happy boy,” Gilkes said on Instagram.
“I look forward to a lifetime of loving you, and learning from you @mariasharpova.”
Sharapova first confirmed her relationship with Gilkes in October 2018, when the couple took a trip to a popular tourist spot in England, the Cotswolds.
Before making their relationship official, the couple were spotted together at an Elton John Aids Foundation event in June 2018, and Beverly Hills in March that year.
Sharapova previously dated fellow tennis star Grigor Dimitrov and Maroon 5 singer Adam Levine.
The Russian has been engaged once before to former NBA star Sasha Vujacic but the pair split in 2012.
Gilkes was previously married to Nonoo — the designer responsible for setting up the Dutchess of Sussex with Prince Harry.
After 13 years together, they split in 2016.