The actor - who plays Nathan Scott on the CW drama - insisted that the cast is appreciative for the show's continued success and does not take anything for granted.
"In the past, we've always had to wait to find out whether or not we would be coming back for another season," he explained to E Online.
"We've gotten used to finishing up seasons with an eye on the possibility that it may be our last. I don't think this season is any different."
Lafferty continued: "I don't see how I could thank the fans enough. They have always kept us on the air. Without them, One Tree Hill doesn't last one episode - let alone eight seasons.
"I will always be grateful and look back on my experience with the show as a defining period in my life."