Greek fan favourites Stefanos Tsitsipas and Maria Sakkari, China's 2023 Australian Open runner-up Zheng Qinwen and Norwegian star Casper Ruud are the first big names to commit to the third edition of the $15 million showpiece.
Alex de Minaur is almost certain to once again lead tournament hosts Australia while nine-time Australian Open champion Novak Djokovic is also in organisers' sights.
Tournament director Stephen Farrow is confident Alexander Zverev will also return to spearhead Germany's title defence and women's world No.1 Iga Swiatek will be back to help Team Poland to try to go one better than this year's runner-up showing.
"I would easily anticipate that, across the both tours, we're going to have somewhere between 10 and 12 top-15 players," Farrow told AAP.
"It's going to be a really, really strong player field again. Going into the third year of this event, it's still an event in its infancy so it takes time to build.
"But the reputation and the engagement certainly from a player perspective, most of the conversations that I'm having are more about when does it start? When am I likely to play as opposed to what is it, which is great."
Jointly hosted by Sydney and Perth from December 27 to January 5, the United Cup has effectively replaced the old Hopman Cup on the Australian tennis calendar.
And just as the Hopman Cup offered the game's top players precious guaranteed court time ahead of the Australian Open, the United Cup appeals to Djokovic and the like because of the round-robin format offering multiple matches win or lose.
The rare opportunity to play mixed doubles outside of the grand slams is also proving a hit with the ATP and WTA stars.
"It's very much on most of the top players' agenda to play next year," Farrow said.
"They're keen to come over to Australia and take part in it and get over here as soon as possible as part of that build-up to Melbourne.
"They're obviously guaranteed at least a couple of matters at minimum, which is exactly right and that's really important as well.
"So we very much hope Novak's back this year and we'll see over the next few weeks.
"And last year we saw a lot of the players who competed and played so well at United Cup then went on and had a really great Australian Open.
"Qinwen is a great example of that. She was actually the first international player to arrive in Australia last year.
"I think she got to Perth on about the 20th or 21st of December and then she was pretty much the last one to leave, which was really cool."
