Justin Timberlake has said that walking away from pop group `N Sync was the "best/worst" decision of his life.

Speaking on TV show Oprah's Master Class, 33-year-old Timberlake said quitting the group who had massive hits with Bye Bye Bye and Girlfriend was one of the biggest risks he's ever taken.

He said: "I would wake up every morning feeling more and more of an urge to step out on my own and try my own hand as a musician just by myself.

"It was happening all around me: 'Why wouldn't you ride this out? You're the biggest group in the world. Why would you walk away from this?'

"It's one of the best/worst things that I have ever done. It was hard to say goodbye to that era, but I felt it changing. I felt music changing. And I felt myself changing."

'N Sync reunited briefly during Timberlake's performance at the MTV Video Music Awards last year.