Three years ago, then 16-year-old Holger Rune received a wildcard into Auckland's ASB Classic qualifying. The world number one junior lost in the final round of qualifying to veteran Canadian Vasek Pospisil.

Still a teenager, he is returning to Auckland in January having lived up to his potential as one of the brightest talents on the ATP Tour.

The Dane is ranked 27th in the world, one place off his career-high of 26 having made the final at the ATP tournament in Sofia earlier this month. He won his first two career titles this year, on clay in Palermo and Munich, before reaching his first Grand Slam quarter-final at Roland Garros in June.

Rune, who has recently started working with Serena Williams' former coach Patrick Mouratoglou, is the third major signing for the men's tournament after world number three Casper Ruud and eighth ranked Cameron Norrie.

Tournament director Nicolas Lamperin says he's a huge talent.

"He was the number one junior when he came here in 2020 having won the French Open and he's been on a roll this year having posted some very good results, winning his first ATP title and beating the likes of Stefanos Tsitsipas and Alexander Zverev," Lamperin said.

"He's been mentored by Patrick Mouratoglou over the years at his academy in the south of France and I would say we are very likely to see him in the top 10 in the years to come. He is very consistent and powerful."

Rune lost to Ruud in an ill-tempered French Open quarter-final, raising the prospect of a rematch in Auckland with both players in the field. Rune gave Ruud a cold handshake after the match in Paris prompting the Norwegian to mouth "you little s***" at the teenager and telling him to grow up.

Lamperin acknowledged it could be spicy if the pair meets in Auckland but felt Rune has matured a lot in the past few months.

"I'm sure people would love to see that rematch after what happened in Paris. Obviously it will be a totally different setting. And I'm not sure the same thing would happen again. But yeah, it would just be a good final to see with two exciting players."

More highly ranked players are expected to be announced for the men's Classic in the coming weeks with the entry deadline six weeks before the start of the tournament (November 28). But the recruitment process has been held up by Tennis Australia's delays in finalising the format and venues for the new ATP and WTA joint venture, United Cup, to be held from late December into the first week of January.

"Some of the players want to wait and have the full picture of what the event is going to look like in Australia, before being in a position to commit for the ASB Classic. There are quite a few discussions going on at the moment," Lamperin said.