Watch: Serena Williams goes head to head with Mike Tyson

Mike Tyson and Serena Williams.

Auckland-bound sporting sensation Serena Williams is one of the hardest hitting players on the global tennis circuit.

And the former world No 1 has also proven she's a hard hitter with boxing gloves on during a workout for boxing legend Mike Tyson.

Tyson – the former World Heavyweight belt holder – has shared a video of the workout on his Facebook page; which has more than 7.7 million followers.

In it Williams, 38, pounds a punching bag with a succession of hefty blows.

The video has been released as the tennis legend prepares to head to Auckland to take on the field at the ASB Classic.

She will return after a poor showing in 2017, losing in the second round and later talking about "abhorrent" conditions she had to play in. That year the tournament was troubled by bad weather.

But off the court things were brighter, with Williams announcing her engagement to Alexis Ohanian from a private beach on Waiheke Island.

One of her tennis besties, fellow former No 1 Caroline Wozniacki today told the Weekend Herald that she was happy Williams would feature in what would be her final showing at the ASB Classic.

Wozniacki recently announced her pending retirement.

"I think she thought about it and she realised that Auckland would be a great place to start the year," Wozniacki told the Weekend Herald from the US. "And, you know, everyone can change their opinion and I think that she is thrilled to be back."

Caroline Wozniacki could be facing off with tennis besting Serena Williams at the coming ASB Classic. Photo / Supplied

Wozniacki's final competitive match will be an exhibition against Serena Williams in Copenhagen in May.

She and Williams became firm friends after the American sought her out to play doubles.

"I mean, she is awesome," Wozniacki said. "She's the nicest person, very thoughtful very sweet, open, honest."

Friendship and fierce rivalry don't always go hand in hand but Wozniacki revealed they have an understanding.

"We told each other that whatever happens on the court happens on the court. First of all we want to win on the court, but off the court you are friends and it is going to be fine."