Retired tennis great Andy Murray has agreed to join Novak Djokovic's team and will coach him at the Australian Open next year, the Serbian 24-times Grand Slam champion said on Saturday.

Briton Murray retired after this year's Olympics in Paris where Djokovic won the gold medal.

The two 37-year-olds, both former world number ones, played each other 36 times, with Djokovic winning 25 matches on the ATP Tour.

"We played each other since we were boys, 25 years of being rivals, of pushing each other beyond our limits," Djokovic said.

"We had some of the most epic battles in our sport. They called us game changers, risk takers, history makers. I thought our story may be over, turns out it has one final chapter," he said. 

"It's time for one of my toughest opponents to step into my corner. Welcome on board, coach Andy Murray," the athlete added. 

Djokovic has won nine of his 24 Grand Slams with Goran Ivanisevic as his coach but the Croatian left his team in March.

"I'm going to be joining Novak's team in the off season, helping him to prepare for the Australian Open," said Murray, a three-times Grand Slam winner and twice Olympic gold medallist.

"I'm really excited for it and looking forward to spending time on the same side of the net as Novak for a change, helping him to achieve his goals," he added. 

Djokovic did not win a major this year and has slipped to seventh in the world rankings.

He will be targeting a record-extending 11th Australian Open crown when the first major of the year begins on January 12.