The Korean hits a flat ball with a particularly strong two handed backhand and he's notched up wins over world number three Sascha Zverev, Gael Monfils, Sam Querrey and David Goffin this year.
Khachanov is a big strong guy in the mould of Marat Safin. He made a fleeting appearance in Auckland this year, losing in the first round but the 21 year old has wins over the likes of Kei Nishikori, Giles Simon, John Isner and Tomas Berdych this year and reached a career high 29 in the rankings in August.
20-year-old Rublev made the US Open quarter finals in September and is the highest ranked of the quartet at 37 while Shapovalov is the youngest at 18 but arguably the most talented. He showcased his ability with incredible wins over Nadal and del Potro at the Montreal Masters in August.
At the moment Shapovalov has the best all court game, the most variety but while it's early days in his development, the signs are promising.
Tournament director Karl Budge has actively pursued the future stars knowing securing the likes of the Federer, Nadal, Murray and Djokovic is unrealistic. It's a wise approach and the signing of the quartet boost a field that has a world class feel to it.
Defending champion Jack Sock has climbed to nine in the world and will play the ATP Finals in London next week while former champions John Isner and Roberto Bautista Agut are both ranked inside the top 20.
It's understood there will be at last one more top 20 player while the eight seeds should all be ranked inside the top 30 with the full field to be finalised later this month.
So far the rival Sydney International hasn't announced a single top 20 player.
Another Next Gen star 20-year-old American Jared Donaldson is also expected to play in Auckland for the first time.