Oprah Winfrey is worth $2.5 billion and has seen much success: She leveraged "The Oprah Winfrey Show" into a booming media and entertainment empire, she has written best-selling books and now she's even creating original content for Apple.

But when she was first starting out, Winfrey toiled away at a job she disliked and even got demoted. In Winfrey's new book "The Path Made Clear: Discovering Your Life's Direction and Purpose," she shares a defining moment in her early career that helped shape the rest of her life.

In the late '70s, Winfrey had been working as a news anchor and reporter at Baltimore's WJZ station. But at that job, she never felt like her authentic self.

"And my bosses certainly made no secret of their feelings," Winfrey writes. "They told me I was the wrong color, the wrong size, and that I showed too much emotion."

Winfrey writes that she felt she was misplaced and never truly felt comfortable with her seat on the 6 p.m. news.

"It wasn't until I was unceremoniously 'demoted' to cohost of 'People are Talking' that I experienced the first spark of what it means to become fully alive," Winfrey writes.

Winfrey's defining moment happened on Aug. 14, 1978, her first day working on WJZ talk show "People are Talking."

Her job as a talk show co-host, Winfrey recalls, felt different than her job as a news reporter. As a reporter, she remembers feeling exhausted and having to drag herself to work. The talk show, however, sparked something within her. During that first show, she interviewed Tom Carvel (the inventor of soft serve ice cream) and remembers feeling "lit up" from the inside.

"When the hour ended, there was a sense of knowing resonating within my heart and radiating to the hairs on the back of my neck," Winfrey writes. "My entire body told me this is what I was supposed to do."

"There was no doubt that the seeds of what was to give my life meaning and purpose had been planted," Winfrey writes. "That day, my 'job' ended and my calling began."

Winfrey shares the story in "The Seeds," the first chapter of her new book. The book is meant to be a guide to creating a life of significance, with each chapter (like "The Whispers" and "The Road") representing a milestone "along the road to self-discovery."

Winfrey says there were other times in her life she felt something new being seeded. For example, years later, at the peak of her success with "The Oprah Winfrey Show," she felt there was something else out there. So Winfrey ended her show in 2011 and went on to build up OWN, her cable network, among other ventures.

"This is the lesson I hope you take away," Winfrey writes. "Your life is not static. Every decision, every setback, or triumph is an opportunity to identify the seeds of truth that make you the wondrous human being that you are.

"I'm not talking just about what you do for a living," she adds. "When you pay attention to what feeds your energy, you move in the direction of the life for which you were intended. Trust that the Universe has a bigger, wider, deeper dream for you than you could ever imagine for yourself."

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