The Highlanders and Southland prop was last night named in the 36-player All Blacks squad to face Tonga and Fiji next month.
He is one of four new names in the team, continuing a remarkable year for the 22-year-old.
He made just two appearances off the bench for the Highlanders last season.
Since getting his chance this year, he has barely put a foot wrong.
De Groot, who was born in Australia but grew up in Gore, has impressed both with his work around the field and at scrum time.
He became a key part of the Highlanders forward pack which went unbeaten through the round-robin of Super Rugby Trans-Tasman.
Joining him in the front row is Otago and Crusaders prop George Bower (29).
Highlanders halfback Aaron Smith and blindside flanker Shannon Frizell were also named in the squad.
Asafo Aumua was preferred to Liam Coltman, while there was no place for Billy Harmon or Jona Nareki.
Other new caps were Blues halfback Finlay Christie, Crusaders flanker Ethan Blackadder and Chiefs centre Quinn Tupaea.
Sam Whitelock will captain the team in the absence of the injured Sam Cane.
The All Blacks play their first test on July 3 against Tonga at Mt Smart Stadium.
They face Fiji at Forsyth Barr Stadium a week later, then a Hamilton test on July 17.
Ethan de Groot
Super Rugby team: Highlanders
Position: Prop
Age: 22
Raised in New Zealand's deep south, the form of 22-year-old loosehead prop Ethan de Groot has been a highlight of the Highlanders’ campaigns this year.
De Groot developed as a player at Southland Boys' High School and rose through the Rugby Southland Academy and age group teams before making his provincial debut for Southland in 2018.
He made two appearances off the bench for the Highlanders last year before becoming a feature of the matchday 23 this year.
The squad - (age, Super Rugby team, provincial team)
FORWARDS
Hookers
Asafo Aumua (24, Hurricanes / Wellington, 1)
Dane Coles (34, Hurricanes / Wellington, 74)
Codie Taylor (30, Crusaders / Canterbury, 56)
Props
George Bower (29, Crusaders / Otago, uncapped)
Ethan de Groot (22, Highlanders / Southland, new cap)
Nepo Laulala (29, Blues / Counties Manukau, 29)
Tyrel Lomax (25, Hurricanes / Tasman, 6)
Angus Ta’avao (31, Chiefs / Auckland, 14)
Karl Tu’inukuafe (28, Blues / North Harbour, 17)
Locks
Scott Barrett (27, Crusaders / Taranaki, 36)
Brodie Retallick (30, Chiefs / Hawke’s Bay, 81)
Patrick Tuipulotu (28, Blues / Auckland, 35)
Tupou Vaa’i (21, Chiefs / Taranaki, 4)
Samuel Whitelock (32, Crusaders / Canterbury, 122) – captain
Loose Forwards
Ethan Blackadder (26, Crusaders / Tasman, new cap)
Shannon Frizell (27, Highlanders / Tasman, 13)
Akira Ioane (26, Blues / Auckland, 2)
Luke Jacobson (24, Chiefs / Waikato, 2)
Dalton Papalii (23, Blues / Counties Manukau, 4)
Ardie Savea (27, Hurricanes / Wellington, 49)
Hoskins Sotutu (22, Blues / Counties Manukau, 5)
BACKS
Halfbacks
Finlay Christie (25, Blues / Tasman, new cap)
Aaron Smith (32, Highlanders / Manawatu, 97)
Brad Weber (30, Chiefs / Hawke’s Bay, 7)
First five–eighths
Beauden Barrett (30, Blues / Taranaki, 88)
Richie Mo’unga (27, Crusaders / Canterbury, 22)
Midfielders
Braydon Ennor (23, Crusaders / Canterbury, 1)
David Havili (26, Crusaders / Tasman, 3)
Rieko Ioane (24, Blues / Auckland, 33)
Anton Lienert-Brown (26, Chiefs / Waikato, 49)
Quinn Tupaea (22, Chiefs / Waikato, new cap)
Outside backs
Jordie Barrett (24, Hurricanes / Taranaki, 23)
George Bridge (26, Crusaders / Canterbury, 10)
Will Jordan (22, Crusaders / Tasman, 2)
Damian McKenzie (26, Chiefs / Waikato, 27)
Sevu Reece (23, Crusaders / Tasman, 8)
