As he bids to win a record-setting 25th grand slam title, Novak Djokovic is bringing in another member of the Big Four as his coach.

In a post on social media, Djokovic announced that longtime friend and rival Andy Murray will be his coach at the 2025 Australian Open.

"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. I thought our story may be over.

Former world number one Andy Murray said he's "really excited" to help Djokovic prepare for the first grand slam tournament of the season.

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

It'll be his first coaching role since retiring from playing in August, after exiting the men's doubles at the Paris 2024 Olympics.

Grew up competing against one another

Both men are 37 and born just a week apart in May 1987.

The pair started facing each other as juniors and wound up meeting 36 times as professionals. Djokovic holds a 25-11 advantage.

Djokovic is level with Australian Margaret Court for the most major singles titles by any player.

He's spent more weeks at number one than any other player in tennis history.

Often referred to as the GOAT, Djokovic has won the Australian Open a record 10 times and beat Murray in four finals in Melbourne.

It would only be fitting for him to overtake Court in Melbourne, where he has enjoyed huge success.

But this season has been difficult by his standards.

Djokovic failed to win a major title for the first time since 2017.

He did however, win his first Olympic gold medal for Serbia in singles at the Paris Olympics, describing it as his "greatest achievement".

The former number one also split from his former coach Goran Ivanisevic in March, and played the rest of the season without a full-time coach.

"I look forward to starting the season with Andy and having him by my side in Melbourne, where we've shared many exceptional moments throughout our careers," Djokovic added.

Fans and players stunned by the news

Fans and players have expressed their excitement for the unexpected pairing on various social media platforms.

"I am so pumped I can't put it into words," one user wrote on Instagram.

"Already picturing him in Novak's box. This is going to be epic!" another said.

Victoria Azarenka wrote "pretty cool" on X, while Canadian player Felix Auger-Aliassime said "so the ATP tour really is a movie".

When is the Australian Open 2025?

The two week tournament will begin on Sunday, January 12, and closes with the men's final on Sunday, January 26.

ABC Sport digital will be live blogging every minute of the action from Melbourne Park.