Duffie had defected from league and the Melbourne Storm at the start of 2016, hoping to push his way into an All Blacks jumper.
He could also become a dual international, having played for the Kiwis in 2011.
"It's awesome, it's one of those things that you never really think is going to happen and you're lucky enough that it does," Duffie said.
"I'm very excited for the next month and what that holds.
"It's also nice for all the people who helped me along the way."
Duffie's achievement is made all the more remarkable by his horror run of injuries while at the Storm, including serious shoulder and knee problems.
Hansen said Duffie had adjusted to rugby with his cool temperament, finishing ability and accuracy in the air to come in handy on tour.
The head coach agreed there was something Ben Smith-esque about Duffie.
"He's done well, coming from the Storm after a lot of injuries - I know they didn't want him to go, they rated him very highly," he said.
- NZN
