In Andrea Bocelli: Because I Believe, which premiered at the Toronto International Film Festival on Saturday, Sept. 7, the Italian tenor opened up about his journey with stage fright.

"I suffered from stage fright for many years. A kind of fear that can't be put into words," Bocelli, 65, says in the documentary.

"An unmanageable anxiety. Vicious palpitations wouldn't let go of me. Even on stage. It would last the entire concert, until the last obstacle," he continues. "This would happen because my technique wasn't perfect."

The turning point for Bocelli was meeting Maestro Pavarotti -- whose real name is Luciano Pavarotti -- and observing his work ethic.

"When I first rehearsed with this great artist, I realized he didn't struggle at all," he says of the late operatic tenor.

"Whilst I struggled a lot. That's when I figured he had perfect technique. I didn't," he continues. "Today, thanks to the technical awareness which I have attained through a lot of effort, I'm stressing this through a lot of effort, I don't have that kind of anxiety anymore."

The documentary, which was directed by Cosima Spender (Palio), "tracks Bocelli's path to success and ongoing dedication to his craft through interviews and archival performance footage, as well as informal gatherings, such as a diverting party where Bocelli's friends and family reminisce over food and wine," according to the film's description.

"When Bocelli sings, it is as though heaven has opened its gates, but watching Because I Believe reminds us that this remarkable artist is very much rooted in the earth," it adds.

Elsewhere in the documentary, Bocelli opened up about the soccer accident in boarding school that left him blind as a young boy.

"One day, playing [soccer], I was the goalkeeper. No idea why, as I had never been the goalie before," he recalls. "And I never would be goalie again. A ball hit me right in the face. From that blow, a hemorrhage.. and the rest is history."

His brother Alberto adds, "That's when he lost. That's when darkness fell."