The three-year-old is part of Serena's training preparations for Australia. (Getty)

As everyone has heard by now, 72 players are in strict lockdown in Australia and anyone freed from their hotel rooms can practice for two hours each day with just one other player for the first week.

But what you didn't know is that Serena Williams chose her three-year-old daughter Olympia as her partner. 

@serena

Footage from my practice before leaving with my training partner @OlympiaOhanian.

♬ original sound - Serenawilliams

Olympia has clearly got a hang for this tennis thing already. She started taking lessons last fall, with her mom on hand, but trying to not get super involved.

In actuality, Serena is training with her big sister Venus in Adelaide this week, though Olympia is on hand for support. 

Serena will play in the Adelaide exhibition at the end of her two-week modified quarantine and then head over to Melbourne.