US Open - Murray to be Djokovic's best man
Local media in both Serbia and Scotland reported that the Scot will be stood next to Djokovic when he weds Jelena Ristic in Kosovo in October.
The world number one's fiancee - who has been his on-and-off girlfriend for five years - is rarely seen at tennis tournaments, instead spending most of her time at the home she shares with Djokovic in Monaco, where she is studying for a masters degree.
As for Djokovic and Murray, their fierce on-court rivalry belies the fact that they have been friends ever since they started facing each other regularly in junior tournaments at the age of 12.
Murray won that first match with ease, but since then Djokovic has gone on to have the greater success.
They still practice and socialise together regularly, even though Djokovic admitted earlier this year that it is difficult to remain friends while being rivals: "The reality is none of us can be real mates while we are fighting for history," he said.
"But one day, when we've all retired, I look forward to sitting down over a beer with them all, and their families, and remember what we went through."