The No. 1-ranked tennis player and six-time major champion is engaged to long-time girlfriend Jelena Ristic, according to his Twitter account.
On Wednesday, Djokovic tweeted a photo of Ristic kissing him on the cheek and wrote: "Meet my fiance and future wife."
After a smiley face, he continued: "So happy! Thank you for wonderful wishes"
This is the 26-year-old Serb's 100th week at No. 1 in the ATP rankings.
He won the Australian Open in January, then was the runner-up at Wimbledon in July, and at the U.S. Open this month.