Tennis stars Serena Williams and Caroline Wozniacki have trained and are 'ready' for their doubles pairing at the WTA Auckland Open.

It was confirmed last month that the pair would team up for the first time at the Australian tournament before Wozniacki retires.

The Danish player announced her retirement last year and said she would stop competing after the Australian Open - though she and Williams will be playing an exhibition match against each other in May in a stand-alone event.

The American tennis legend took to Instagram to make sure her partner was training hard for their partnership. In a video Williams said: "Hey Carol, hope you're practising your volleys, I am. I'm getting ready, legendary doubles matches coming up."

Wozniacki responded to her long-time friend in a clip in which she said: "Oh Serena, I love that you've been getting your work in. I too have been working on my volley game so I am so ready for Auckland for our doubles, let's go!

"I've been working really really hard and I'm pumped. I'm pumped to play with you Serena and I'll see you soon."

As well as training for one of her final competitions, Wozniacki has been featured in Sports Illustrated in a risque photo shoot. 

The WTA Auckland Open begins on January 6.