Aussie tennis stars John Millman and Alex de Minaur have a strong bromance cultivated over years on the ATP Tour - and now that friendship has been put to the test on live television.

De Minaur has surged into the fourth round of the Australian Open and will face nine-time champion Novak Djokovic while Millman fell in the second round to two-time finalist Daniil Medvedev.

Milman joined the Channel 9 panel to chat about the Open with host Tony Jones and tennis greats Alicia Molik and Todd Woodbridge when Jones thought it would be a great idea for the Aussie star to give his mate de Minaur a call live on air.  

'Now we want to put you to the test, you say you're pretty good mates with him?' he asked.

'I think so,' Millman replied.

'Is he on speed dial on your phone?' Jones asked.

'Um, I've got his number but he didn't answer me yesterday,' Millman replied.

'Try it, let's see if he answers,' Jones replied.

Millman was briefly reluctant, saying 'nah, nah' but even then he was reaching into his pocket for his phone. 

'I can guarantee you he is not going to answer because he might have some bigger things to worry about today,' Millman said.

However, to the panel's surprise, de Minaur picked up straight away.

'Hey, here he is. Look we're on set today Alex and we just want to wish you the best of luck buddy,' Millman said.

'Are you watching?'

Then, to the panel's surprise, de Minaur revealed he was watching his good mate live on television.

'You look really good on TV, I love the way you've done your hair this morning,' he said.

Former Australian women's player Alicia Molik then turned the conversation toward the Monday night showdown in the round of 16 against Novak Djokovic.

'Any words for Novak, Alex?' she asked.

De Minaur's response was inaudible, but he then credited for Millman for teaching him how to play against the Serbian champion.

'It's going to be fun and Johnny's told me how to play him,' de Minaur said.

'I am about 0-4 against him, so take what I say with a grain of salt, mate,' Millman laughed.

It is not the first time Millman has playfully grilled his Australian teammate. 

Previously, on an episode of ATP Uncovered, Millman ripped on everything from de Minaur's dance moves to his driving skills.

In an hilarious interview, Millman asked about de Minaur finally getting his driver's licence.

'First of all I want to know how you managed to do that because I reckon you're a pretty average driver from what I've heard,' he asked.

'I'd like to inform you that I'm a very good driver, OK? Six days of driving and I haven't crashed yet,' de Minaur replied.

Millman followed up exposing de Minaur's secret dancing skills, which were recently revealed in his hilarious Davis Cup initiation ceremony.

'I've seen it firsthand you are definitely one of the best dancers on tour and it's not even a debate,' Millman said.

De Minaur then challenges Millman to show him his signature dance move, with his Aussie mate then proceeding to drop the classic sprinkler.

'You've got to put more energy into it,' de Minaur laughed.