World No.7 Stefanos Tsitsipas and world No.6 Maria Sakkari will lead No.2-seeded Greece. The team will also consist of Stefanos Sakellaridis, Petros Tsitsipas, Despina Papamichail and Valentini Grammatikopoulou.
Defending champions, the United States featuring world No.4 Jessica Pegula and 10th-ranked Taylor Fritz, seeded third.
Grand Slam giants Novak Djokovic of Serbia and Iga Swiatek of Poland will also star in this year’s United Cup.
Team Poland, led by world No.2 and four-time Grand Slam champion Swiatek and  Hubert Hurkacz, have been named as the top seeds for the 2024 edition after the entries from the top 16 countries were revealed today.
France, the No.4 seeds will be steered by world No.10 Caroline Garcia and  Adrian Mannarino.
Wimbledon champion Marketa Vondrousova will headline the Czech Republic team alongside  Jiri Lehecka.
And Croatia rounds out the top six, featuring  Borna Coric and  Donna Vekic.
Australian world No.13 Alex de Minaur, Ajla Tomljanovic and John Millman, as well as doubles stars, world No.2 Storm Hunter, world No.6 Matt Ebden and world No.24 Ellen Perez will fly the flag for the green and gold.
Four countries will make their debut in 2024. Serbia, led by 24-time Grand Slam champion Djokovic and Olga Danilovic, and Canada, featuring  Felix Auger-Aliassime and Leylah Fernandez, will compete for the first time, along with China’s  Qinwen Zheng and Zhizhen Zhang and Netherlands’  Talloon Griekspoor and Arantxa Rus.
Other standout entries include Norway’s  Casper Ruud, Germany’s Alexander Zverev and Angelique Kerber and Great Britain’s Cameron Norrie and Katie Boulter.
The top five WTA ranking-qualified countries, top five ATP ranking-qualified countries and the top six combined entry countries have been admitted to the competition.
The final two remaining countries (one WTA and one ATP) will be decided on Monday 20 November, based on the rankings published on this date.
“Wow, what a fantastic field we have for the United Cup in 2024, this will be an exciting and unmissable tennis experience this summer,” United Cup Tournament Director Stephen Farrow said.
The United Cup, an ATP-WTA event presented in partnership with Tennis Australia, offers a minimum AUD $15 million in prize money and 500 Pepperstone ATP and 500 WTA Tour rankings points.
Eighteen countries will contest the second edition with each city to host nine teams – three more than 2023. Each team will comprise up to three men and three women.
Countries will be drawn into six groups of three countries and will compete in a round-robin format.
New for 2024 – each tie will be determined in one session and will include one men’s singles and one women’s singles match featuring the No.1 ranked singles players, followed by one mixed doubles match.
Perth’s RAC Arena will host the first day of the United Cup on Friday 29 December, with the group stage in Sydney beginning on Saturday 30 December.
Group winners in each city will advance to the quarterfinals, with one quarterfinal spot in each city awarded to the best runner-up in that city.
Winners will progress to the semifinals and finals in Sydney, which will be played on 6 and 7 January.