The pop singer has posed for a new hard-hitting poster which shows her wearing a stunning black dress and holding up a skinned fox.
Underneath her picture are the words: 'Here's the rest of your fur coat'.
Fur making a comeback
Sophie, who used to be a model, said: "I think fur is really pathetic when there are so many alternatives.
"To me it felt a very natural thing to do, to be on the side of animals when it came to fur."
Anti-fur campaigners are worried that fur is making a comeback in the fashion world.
For years it's been considered unacceptable, but fur's been seen on the catwalk and in some fashion magazines over the last couple of years.