The former Ajax goalkeeper joined Barca last week.
"At the start, it seemed strange that the best team in the world wanted to sign me, I thought it was a joke."
The Dutch keeper told the official club website that he is convinced that he will adapt well to Luis Enrique's team, as he comes from a similar philosophy of play.
"Barça and Ajax are two teams with a comparable style, and this will make the adaption easier for me. I know this style of play well, I know what Barça expect in a keeper and I will try to do well.
"I don't think I am a typical keeper, I can play with the ball and that is important at Barça."