The 26-year-old actress said she was specifically told to "lose weight" and "change the shape" of her face if she wanted to bag the big roles and become a household name.
"I felt very lucky and grateful, and couldn’t believe that I had got this top-of-the-game job..." she said.
"[But] all the things that they were trying to change about me, whether it was my weight, my look, the shape of my face, the shape of my eyebrows, that was so not what I wanted to do, or the industry I wanted to work in."
The Don’t Worry, Darling star, who has this week opened up about her early days in the entertainment industry, landed her first big role in 2014 movie The Falling.
She went on to land a part in a US TV movie Studio City, but was so disappointed in her experience on the show that she feared she’d made the wrong career choice.
She added to The Telegraph: "I’d thought the film business would be like [my experience of making] The Falling, but actually, this was what the top of the game looked like, and I felt I’d made a massive mistake."
She added: "I think it’s far too easy for people in this industry to push you left and right and I was lucky enough to discover when I was 19 what kind of a performer I wanted to be.
"When I could be naked at whatever size I was, and bare-faced, and the acting could speak for itself.
“There’s nothing for people to be distracted by: they can’t be like, ‘Oh, I don’t like the make-up’. It was a wonderful reminder: ‘Oh, yeah - this is who you are’."