The former Juventus midfielder has already made his debut in last week's Joan Gamper Trophy victory.
Pjanic told Mundo Deportivo: "To be chosen by Barça at any time is very important, because we know very well that the players here have to have certain qualities and a certain level of play.
"Being chosen was a great pride for me. This is a very important opportunity that I have had in the past, but it has not been able to materialise. We have spoken to Barcelona two or three times already, but one thing is to speak and another is to achieve. It's different and difficult. But it was not possible to come before because the other club did not want to listen to the offers, football is like that.
"When this new opportunity presented itself, I accepted this new experience because for me it is a dream to play at Camp Nou and for me in the biggest club."