The Danish athlete (27) and NBA star (34) went public with their romance eight months ago, but it's unclear how long they were keeping their relationship under wraps prior to that. Wozniacki shared a close-up image of her jaw-dropping ring, with the caption, "Happiest day of my life yesterday saying yes to my soulmate."
Lee was equally excited after popping the question, sharing a picture of them on a boat in Bora Bora in their first picture as an engaged couple. "She said YES! So thrilled to be engaged to my soulmate," he wrote.
It's the second engagement for Wozniacki, who was due to wed Irish golfer Rory McIlroy before he called it off in 2014. He wed American PGA employee Erica Stoll earlier this year at Ashford Castle in Co Mayo. McIlroy blamed himself for ending the relationship, saying at the time: "The problem is mine".
"The wedding invitations issued at the weekend made me realise that I wasn't ready for all that marriage entails."
Wozniacki has reason to celebrate both personally and professionally - just last month, she defeated Venus Williams in the championship match of the 2017 WTA Finals and has been having one of her strongest years on the court.