
Rex Features
The former model believes carnivores are responsible for global warming and must change to a plant-rich diet to solve the problem.
She is to star in two adverts for Vegetarians International Voice for Animals (Viva!), the first of which features the line: "Hey Meaty, you're making me so hot!"
She makes fun of the loss of her leg in the second advert, warning non-vegetarians: "You haven't got a leg to stand on!"
Mills, 39, will also appear at Speaker's Corner in London's Hyde Park on Monday to lecture on the environmental impact of eating meat.
Viva! claims a vegetarian diet can halt global warming, which the group believes is caused by methane from flatulent cattle.
It has also been revealed that Mills turned down an opportunity to feature in a TV documentary with Louis Theroux.
The filmmaker said: "I approached Heather the day after her divorce was announced last year. I think she should put herself forward more. It would have been a good one to see how her PR people were handling everything."





