Zack Steffen thought his agent was joking when he told him Manchester City were interested in signing him.
After spending a season on loan with Fortuna Dusseldorf, the American is now City's number two behind Ederson.
Discussing his move to England with Soccer Bible, Steffen has said: "It's definitely surreal. There have been some times where I've had to pinch myself and be like, wow, this is actually reality.
"But when I first heard that Man City were interested in me, yeah, that was surreal and I thought my agent was joking!
"When I got over here and signed and checked everything out, that was insane.
"When I got here for pre-season, got in the Man City locker room and met everyone and saw what their daily routines are and their habits - very surreal."
On working under Pep Guardiola, Steffen added: "Yeah, I mean I was nervous.
"At first it was kind of intense, just because of the stage and the pedestal that we put him on, but he's a good guy, very passionate about his players and very, very passionate about the sport.
"He's a relentless winner. A perfectionist. Always thinking about tactics, about how we can break teams down. He hates when other teams have the ball."