Reece comes into the team for his second test at the expense of veteran Ben Smith who was left out of the matchday 23 after a below-par performance during last week's 47-26 defeat to Australia in Perth.
The must-win Bledisloe Cup rematch will be Reece's last chance to show coach Steve Hansen why he deserves to be on the plane to Japan as part of the All Blacks' 31-man World Cup squad which is named on August 28.
But Reece's mind is solely focused on helping the All Blacks retain the Bledisloe Cup at Eden Park on Saturday.
A win against the Wallabies will see the All Blacks retain the Bledisloe Cup, while a loss or draw will see the trophy head across the Tasman for the first time since 2002.
Speaking to Newshub at a fan day event in Auckland, Reece admitted he never thought he'd get the chance to play in such a big test so early in his career.
"Steve told me after training," said Reece. "When my name got called out, I was like 'oh that's my name, I'm going to start'. I'm really looking forward to it.
"I've just been training hard every day, and I didn't think this would come around so fast, especially in a big game decider, it is unbelievable and special.
"Being able to start in a big game is really special, not just for me, but for my family."
The inclusion of Reece was one of many big changes Hansen made to the team in order to retain the Bledisloe with Rieko Ioane and Owen Franks both missing out in favour of George Bridge and Nepo Laulala respectively.
All Blacks fullback Beauden Barrett said while it is disappointing for Smith to miss out, he is excited to see what Reece can do on the big stage.
"With Ben not being there you lose a lot of experience and a very calm head, but on the other hand you have a very excited Sevu Reece," said Barrett.
"Ben is a class player, and he will be back in no time, but I'm excited about seeing Sevu go."
Fellow All Black Richie Mo'unga spent the entire Super Rugby season with Reece at the Crusaders, and the playmaker has been impressed with what he's seen from the Fijian-born winger.
"His eagerness to learn. His knowledge of the game can be underestimated, and he brings a lot of value," he said.
"His energy on the ball is awesome, and the fact he can turn something from nothing is what has given him the year that he has had.
"He's a humble kid and works really hard and just wants to learn. I'm really impressed with him."