In honor of the milestone, Winfrey is taking a walk down memory lane in the latest episode of her podcast, looking back at how it all started, including the audition tape that helped change the course of her career.

"Oprah had nothing prepared for the audition that changed her life," reads the setup to a clip shared on Instagram, which features Winfrey's September 1983 audition tape for Chicago's AM Chicago. And judging by the VHS footage, she didn't need much preparation.

"Forty years ago today, The Oprah Show debuted, and in honor of that day, we are taking a walk down memory lane on our latest episode," reads the caption accompanying the video, which features Winfrey reflecting on the early days of her career and the audition that brought her to Chicago.

"Hi there. My name is Oprah Winfrey. Oprah, spelled O-P-R-A-H, and if you notice, it's Harpo spelled backwards," a young Winfrey says directly into the camera. "My folks did not particularly like Harpo Marx. We did not even have a television set for a number of years."

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She then explains the story behind her unusual first name.

"Originally, I was named from the Bible by Aunt Ida, who named me from Ruth, the first chapter at the 14th verse, Orpah, but no one knew how to spell in my home, and that's why I ended up being Oprah," she says.

Winfrey also gives her prospective Chicago employers a quick rundown of the journey that brought her to that moment.

"I was born in Kosciusko, Mississippi. I was raised by my grandmother for the first six, seven years of my life on a farm in Kosciusko. It's been a long way getting to Chicago."

Then comes a glimpse of the humor and personality that would eventually make her a daytime TV phenomenon.

"Most of my teen years, I grew up in Nashville, Tennessee, which was very interesting. I had a very strict father who believed I shouldn't date until I was 16, and I was 36-22-36 at age 14 — oh, to die, to die, to die," she jokes. "And after being in Baltimore for seven years, I'm ready to come to Chicago. Bye."

More than four decades later, Winfrey couldn't help but notice another important piece of history in the old footage: the outfit.

"See that black-and-white outfit? That was Anne Klein II, for those of you old enough to remember Anne Klein the designer," Winfrey recalls. "That was Anne Klein II, the second line. It was cheaper than Anne Klein."

And she definitely got her money's worth.

"I was so happy about that Anne Klein II outfit! I wore it for the audition. I wore it for every special occasion," she says, pointing out that she even wore it for an interview with Barbara Walters. "I wore that thing until I couldn't wear it anymore."

The audition worked. Winfrey relocated to Chicago to host AM Chicago, eventually transforming the struggling morning program into a ratings success. In 1986, it was renamed The Oprah Winfrey Show and launched nationally, beginning a television run that would last until 2011.