Australia's Cup campaign begins on Friday night with a match-up against Great Britain at Perth's RAC Arena.
Adding intrigue to the tie is the fact that de Minaur's girlfriend - world No.56 Katie Boulter - will play for Great Britain.
De Minaur played down any prospect of featuring in the mixed doubles against his girlfriend when asked about it on Wednesday, with Matt Ebden and Storm Hunter set to team up for Australia.
British tennis player Katie Boulter is going out with Australia's top-ranked player Alex de Minaur. (Dave Hunt/AAP PHOTOS)
But on the eve of the tournament, de Minaur left the door ajar for that dream face-off against Boulter to happen.
"Well, you never know until you sign on the dotted line, come that mixed (doubles)," a cryptic de Minaur said on Thursday.
"I could be an option (for the doubles). I have played mixed in the past with Katie, so I know all her weaknesses!
"I've watched enough of her matches to know the spots to be attacking. If we step out on court, it's just all business."
It was at this point that Millman stepped in to put the heat on his friend.
"My missus doesn't have any weaknesses. That's pretty brave of you to say that (about Katie)," Millman said.
"You're in trouble. (You) might be sleeping on the pullout in my room tonight."
Australian John Millman has announced he will retire from international tennis. (Lukas Coch/AAP PHOTOS)
Jokes aside, Millman is thrilled to be in the same team as de Minaur for what will be the 34-year-old's final summer of tennis before he retires.
"Throughout my career I've seen him grow from being an Orange Boy to now being Australia's No.1 tennis player, really knocking on the door to that top 10," Millman said.
"He's been one of my closest mates. To do this dance one last time with him is going to be a lot of fun.
"I couldn't think of a better bunch of people to go out and represent the green and gold. It will be a lot of fun."
For Ajla Tomljanovic, it's a case of making up for lost time after her 2023 was largely wiped out because of a knee injury.
"It just makes me more excited to be back," she said.
"I think the month of January is always the month I want to do my best. That's never changed.
"Having a bit of time off just makes me more motivated."
Tomljanovic holds a 1-0 advantage over Boulter after beating her 6-3 6-4 on grass in 2022.
"She's coming off of her best year. It's going to be a really tough match," Tomljanovic said.
"She's got a big game. I'm just looking forward to getting out there and doing my best."
Spain will take on Brazil during Friday's day session in Perth, with the action in Sydney to start from Saturday.
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