She may be a global superstar who's won a shelf full of Grammys, but Alicia Keys says she has insecurities just like everyone.

While sharing an excerpt from her new book "More Myself: A Journey," the chart-topping singer sat down with People magazine to discuss the self-doubt she's held on to since her childhood.

Throughout her 20-year career, Alicia Keys has evolved from the girl with the braids who sang "Fallin'" to a powerhouse writer, producer, songwriter, entrepreneur, philanthropist, wife and mother.

But in "More Myself," she talks about her lifelong struggle to love herself: a struggle that started when she was a kid growing up in New York's Hell's Kitchen with an absentee father.

"For me, a seed of worthlessness was planted in childhood," she writes in her new book. "As well-intentioned as [my father] Craig [Cook] was, and as much as he was dealing with in his own life, his absence impacted me in ways I’m still uncovering. It left a hole in me."

It was during the peak of her career in 2006, Keys says, that she came to a realization.

"I was building my life around this image of perfection and it was really oppressive," she told People. "I was clearly a woman who wanted to talk about truth and empowerment and strength, but when I really looked at myself, I realized that my whole life, I’ve kind of been putting on a mask."

These days, the singer is confidently moving toward becoming who she truly wants to be. "I feel more like an open book. That’s a beautiful thing," she told People.

Keys recently postponed her book tour and her upcoming album "ALICIA." The audio version of "More Myself: A Journey" is available now. The book comes out Friday, March 31.