If you thought Kelly Clarkson's bid on American Idol was her first shot at singing stardom, you'd be wrong — by the time she made it onto the show, she'd already been pursuing a career for nearly a decade, entering opera competitions for scholarship money and waitressing at comedy clubs to make ends meet.

Still, in a new interview with Cosmopolitan, Clarkson admitted there is one moment she experienced as a teenager that cemented her love of music, and it involved a stranger's insistence that she'd one day be a big deal.

After Kelly's first solo performance, during which she sang Mariah Carey's "Vision of Love," she said an older man — someone whom she expected to be a friend's grandfather — delivered a compliment that completely changed her life.

“That was so amazing, you’re gonna do this for the rest of your life,” he told her. And she was so incredulous she didn't know how to react.

“I don’t even think I said ‘thank you.’" she said. "I was taken aback because I’d never received any kind of compliment like that."

And 15 years into her career, Clarkson says she still points to the moment as her career's most formative inspiration. She adds things might have not gone exactly the same if the stranger hadn't issued such a proclamation.

“It was a really pivotal moment for someone to come up to me and instill that confidence at such a young age," she said. "From that moment, all I focused on was singing, whether it was getting a scholarship for college or trying out for [American] Idol.”

Clarkson added she's since spent a lot of time trying to find the man, but has come up short. Now, she wonders if she imagined him.

“Was he real? We all have these moments in our life that are so pivotal…that really was that fork in the road that sent [me] on a completely different path,” she said.

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