Tyra Banks was rejected by "six agencies" at the start of her modelling career.
The 'FabLife' host, who turned to TV presenting after retiring from the catwalk in 2005, admits she has faced a lot of obstacles in the past.
Asked what doors were locked to her before she found fame, she said: "Oh, so many. There was a door that was locked because I was a young black model and the first six agencies I knocked at said no - I think four of the six said, 'We already have a black girl.' And then once I was successful, designers were like, 'You're getting too thick.'
"When I wanted to be a television producer, I had a lot of people tell me, 'Oh, you're a model, you could never do that. You walk runways in your underwear.'"
The 41-year-old star, who graduated from Harvard Business School in 2012, is very ambitious and decided to go back to university because she wanted to have a self-funded company.
She explained: "I'm obsessed with ownership. I want to have the say, not just a say. So I needed to have the tools. I want to be a really strong leader."
Asked what she would tell her 25-year-old self, she told the December issue of Glamour magazine: "Take some time for yourself. You're still gonna be successful if you go on that vacation."