The 71-year-old is currently promoting her memoir, which takes in everything from her childhood and modelling career to her time working with the style bible's editor Anna Wintour.
In an interview with The Observe newspaper, Grace was quizzed about the ongoing debate over thin models. Although she insists helping women have a good body image isn't her job, Grace understands there is an issue within the industry.
"I'm not here to teach people anything. I photograph what I think is right, and if a girl is anorexic I'm not going to feel right about it, so I wouldn't book her. But I wouldn't book one that is too fat either," she said.
"There are people who are very guilty of working with girls who are too thin, just because the camera always makes people look that little bit fatter than real life. Some 16-year-olds go too far – they can't see what's right in front of their eyes, and it's dangerous. But some young girls have no shape whatsoever – they're like little boys, and I hate to say it, but the clothes hang well on them."
Grace is a famous lover of cats and even has special outfits for her felines. Her dedication to the animals impacts her opinions of using fur in her shoots, which she will steer clear of wherever possible.
The star's interest in cats is also detailed in her book, where she discusses cat psychics.
"I was told to take the cat psychic stuff out of the book because everybody would think I was a kook," she laughed. "But it's just that sometimes when the thing you love is ill, you reach out for a little more knowledge of what's going on."
Anna Wintour recently gave an interview in which she explained she likes to work with strong people with opinions. Grace confirms that is right, adding showing a softer side wouldn't get a person anywhere with the fearsome editor.
"I bore her to death. I don't cuddle her, no. She wouldn't respond to that. You have to present to her in a strong way – eventually if it's right you'll convince her," she said.