The ATP and WTA, organizers of tennis’ top men’s and women’s tours, have teamed up with national governing body Tennis Australia to launch the United Cup, an annual mixed-gender national teams tournament to be held across Australia.

The new tournament, which was first reported last month, will feature mixed teams from 18 countries that will compete from December 29, 2022, to January 8, 2023, in Brisbane, Perth, and Sydney.

It will act as a warmup event to the season-opening grand slam The Australian Open, which starts on January 18 at Melbourne Park.

ATP chairman Andrea Gaudenzi said: “The United Cup marks a major step forward for the game of tennis.

“Most importantly, it will create incredible new experiences for our fans. We’re excited to see the best men’s and women’s players competing together, with ranking points on the line, to launch the season like never before.

The new tournament will have a prize purse of $15 million, and unlike the Hopman Cup, will offer both ATP and WTA ranking points.

The teams will feature up to four players from each tour and the first countries to qualify will be based on the six highest-ranked players on both tours.

Each tie will comprise two men’s and two women’s singles matches and one mixed doubles match. Each Australian city will host two groups of three countries, competing in a round-robin format.

Group winners in each city will then compete in a playoff for one of the three ‘final four’ spots. The three city champions will then advance to the semi-final stage along with the next best-performing team from the playoffs.

The final will take place at Ken Rosewall Arena on January 8.

Tennis Australia chief executive Craig Tiley said: “The United Cup presents a unique opportunity to unite both the men’s and women’s tour in a brand-new way that has never been seen before.

“We have the opportunity here in Australia to leverage tennis’ unique position to allow the world’s top men and women to compete side by side and represent their country at the highest level.

“We couldn’t be more delighted to see how this even unfolds in January across Brisbane, Perth, and Sydney.”

The competition, which replaces the men’s discontinued ATP Cup on the tennis calendar, is a revival of the Hopman Cup which was held in Perth from 1989 until 2019 before it made way for the ATP Cup.

Earlier this year, it was mooted the ATP Cup would be cut or reformatted due to falling interest from players and fans. Domestic commercial broadcaster Nine Network said less than 95,000 viewers tuned into their coverage of primetime sessions during this year's tournament in Sydney across its free-to-air channels Nine and 9Gem.

Meanwhile, the ATP today announced two changes to its 2023 calendar.

The ATP 250 Sofia Open, which was played from September 26 to October this year, will be cut from next year’s calendar. It will be replaced with a yet-to-be-finalized ATP 250 tournament in Australia that will be played at the same time as the United Cup to provide “additional playing opportunities in the swing ahead of the Australian Open”.

The ATP 250 Serbian Open scheduled to start on April 17 has been relocated to Banja Luka in Bosnia and Herzegovina.