Novak Djokovic will prepare for a tilt at an 11th Australian Open title by representing Serbia at the United Cup mixed team tournament while old rival Rafael Nadal and former women's world number one Naomi Osaka return at Brisbane after time away.
Djokovic enjoyed a spectacular 2023, winning three out of the four Grand Slams, starting with his triumph at Melbourne Park, but unlike last season when he warmed-up at Adelaide, the 36-year-old headlines the 18-nation event that begins on Friday.
Nine of the world's top 20 men's players, including 24-times major champion Djokovic, Melbourne runner-up Stefanos Tsitsipas, world number seven Alexander Zverev and world number 11 Casper Ruud will play in the second edition of the $10 million event.
World number one and French Open champion Iga Swiatek leads the big names among women as she bids to guide Poland to victory in the revamped event that will feature fewer matches this year and take place in Perth and Sydney.
Wimbledon champion Marketa Vondrousova, Jessica Pegula and Maria Sakkari will also be in action.
Spain meet Brazil on the opening day before Britain take on hosts Australia.
The United States are the defending champions after beating Italy in a one-sided final last time out.
Nadal endured two defeats in the inaugural edition before a hip injury at this year's Australian Open decimated his season and the Spaniard makes his much-awaited comeback at the December 31-January 7 Brisbane International where he last played in 2017.
The injury-plagued 37-year-old underwent surgery in June and expects 2024 to be his final season on tour.
The Brisbane tournament, which returns to the tennis circuit as an Australian Open warm-up for the first time since 2020, will also mark Osaka's return after a break of 15 months.
The four-times Grand Slam champion last played a WTA event at the Pan Pacific Open in Tokyo in late September 2022 and had a daughter in July this year.
She will be joined in a packed field by reigning Australian Open champion Aryna Sabalenka, while US Open holder Coco Gauff begins her season at the Jan. 1-7 Auckland Classic.
Men's world number two Carlos Alcaraz, who denied Djokovic a clean sweep of the Grand Slams with his Wimbledon triumph, will head to the Australian Open beginning January 14 without playing a tune-up event having missed this year's edition with injury.
