Emma Watson has revealed that she once considered quitting the Harry Potter franchise.

During the upcoming Harry Potter 20th Anniversary: Return to Hogwarts special, the actress confessed she considered quitting her role as Hermione Granger in the movie franchise around the time they made 2007's Harry Potter and the Order of the Phoenix.

"At times, I was lonely," she explained. "I think I was scared. I don't know if you ever felt like it got to a tipping point when you were like... 'This is kind of forever now'."

The Little Women star decided to carry on with the films without any outside influence.

"The fame thing had finally hit home - in a big way. No one had to convince me to see it through. The fans genuinely wanted me to succeed and they all genuinely have each other's backs. How great is that?" she said.

Her former co-star Rupert Grint was surprised by Watson's revelation and admitted he had similar thoughts about calling time on his stint as Ron Weasley.

"We never really spoke about it, I guess we were just kind of going through it at our own pace, and we were kind of in the moment at the time. It just didn't really occur to us that we were all probably having similar feelings," he shared.

David Yates, who directed Order of the Phoenix as well as the subsequent three instalments in the franchise, backed up Watson's story by revealing that he'd been warned about her uncertainty.

"One thing that (producer) David (Heyman) and the studio spoke to me about was Emma is not sure she wants to come back to do another Potter," he added.

Harry Potter 20th Anniversary: Return to Hogwarts airs on 1 January.