So where's the ring, Serena?

Serena Williams kept her left hand in her pocket all the way through Auckland Airport this morning and to the waiting car. Photo / Michael Craig

She was happy to announce her engagement to the world, but tennis superstar Serena Williams may be less keen to share news about her ring.

The world's highest-earning female athlete was met by a large media contingent when she touched down in Auckland early this morning to prepare for next week's ASB Classic.

At that point, news of her engagement to Reddit co-founder Alexis Ohanian had yet to emerge. Even so, Williams appeared to be expecting the global interest it would precipitate.

It wasn't obvious at the time, but a review of video of her arrival shows she kept her left hand carefully hidden throughout the few minutes she spent walking through the public arrivals area at the airport to her waiting transport.

Screen grab of Caroline Wozniacki and Serena Williams arriving at Auckland International Airport this morning ahead of the start of the ASB Classic tennis tournament.

As she emerged from the Customs and biosecurity hall alongside Caroline Wozniacki, Williams' left hand was kept in a pocket of her grey tracksuit top.

Coincidence? Possibly. But it's unlikely given the way celebrities of her status manage media coverage.

Either way, there are two big unanswered questions. Was she even wearing an engagement ring? And, if so, what did it look like?

It's a fair bet that if there is one, it's nothing to be ashamed of. As well as co-founding Reddit, Ohanian - a 33-year-old New Yorker - has more than 100 other tech start-ups in his portfolio.

US tennis star Serena Williams training at the ASB Tennis Centre. Photo / Dean Purcell

According to the Celebrity Net Worth website, Ohanian has a net worth of US$6 million, although that's small compared with his fiancee's estimated US$150m fortune.

Williams cancelled a scheduled promotional appearance in Auckland this afternoon but had a first training session at the ASB Tennis Centre, where the Classic will be held.

Keeping her left hand hidden wasn't an option then, but there was no ring on the fourth finger, although there were some on her right hand.

ASB issued a statement confirming a celebrity doubles match between Serena and Venus Williams and All Black brothers Ardie and Julian Savea will still take place at the centre on New Year's Day.