Organisers are hopeful Carlos Alcaraz will join a growing list of stars at the restored Brisbane International before entries close for the Australian Open lead-in event next week.
This year's Australian Open women's finalists Elena Rybakina and Aryna Sabalenka, as well as exciting American Ben Shelton were confirmed as starters on Tuesday.
They'll join Naomi Osaka, Victoria Azarenka, Andy Murray and Holger Rune at the popular tournament, which hasn't been staged since 2020.
The December 31-January 7 showpiece is back on the calendar as a stand-alone event after the COVID-19 pandemic forced a shift to multi-city team events.
World No.2 Sabalenka and No.4 Rybakina will return as strong Australian Open chances, while 21-year-old Shelton's big-time tennis saw him blast into the quarter-finals at Melbourne Park this year and then reach the final four of his home slam.
"It brings credibility to a women's draw that was already strong," tournament director Cameron Pearson told AAP.
"And Ben's got the game for this court; it will really suit him.
"He owns the court, he's got the swagger. He'll be a fan favourite and I genuinely think he'll be a grand slam champion in the next few years."
Entries close within a week and world No.2 Alcaraz is yet to confirm where he will launch his Australian Open preparation.
It won't be at the United Cup - being played at the same time in Sydney and Perth - because the Spaniard wasn't included in the country's squad.
"Obviously he's a quality player we'd love to see in Brisbane," Pearson told AAP.
"We've got another week, let's see what transpires."
Alcaraz this season denied Novak Djokovic the first calendar-year grand-slam sweep since Rod Laver in 1969.
His epic five-set Wimbledon final defeat of Djokovic, which was the Serb's only loss in 28 matches at the majors in 2023, has the 20-year-old halfway towards completing his own career slam.
He removed Australian great Lleyton Hewitt from a page in the tennis record books by becoming the youngest-ever world No.1 - at 19 years, seven months and four days - after winning the US Open in 2022.
"We're really bullish with what the draw looks like. I'm excited by what the fans will be coming to watch," Pearson said.
"Each player has their own prep. Some like being guaranteed two matches (at the United Cup), versus a tour event where you step on court and if you don't win you're out.
"Let's see what he (Alcaraz) wants to do."
Former winner Nick Kyrgios remains an outside chance of featuring, with Pearson able to award the rehabilitating Australian one of three wildcards at any stage before the first round.
