Welwyn Garden City's Alesha Dixon and Essendon's Simon Pegg are among the stars calling for a UK ban on animal fur imports.
Dame Judi Dench, Joanna Lumley, Ricky Gervais are also among the 31 celebrities who have signed an open letter to the Prime Minister.
It's already illegal for some furs to be brought into Britain - but that from animals including foxes, rabbits and minks is permitted.
Part of the letter reads: "Mrs May, the animal fur arriving in British ports is from animals who have suffered a lifetime in tiny barren cages, often driven insane by neglect. It is from animals who have been brutally electrocuted or gassed, and sometimes even skinned alive. It is from animals caught and left for days in barbaric leg-hold traps. They endure all of this to then have their fur processed into a frivolous trim on a hat, coat, shoe or handbag. We should not trade on their suffering".
Claire Bass, executive director of Humane Society International UK, said: "We are delighted that so many of the UK's best-loved celebrities have spoken out in favour of a Fur Free Britain. Their words echo the calls from the vast majority of the British public who want to see an end to animal fur being imported onto our shores.
The UK banned fur farming almost two decades ago because of animal suffering, but we continue to import that same cruelty from other countries such as Canada, China, Poland, and the US, where the appalling suffering continues. We urge Theresa May and her government to put an end to this double standard".
The #FurFreeBritain campaign is calling on the government to make the UK a fur-free zone by extending the existing bans on imports of cat, dog, and seal fur to all fur-bearing species.
The campaign is already gaining traction in Westminster; this month, the Environment, Food and Rural Affairs Committee is conducting an enquiry into the UK fur trade. It has also gained support from a growing list of MPs of all political colours, including Conservatives Zac Goldsmith and Sir Roger Gale, Labour's Kerry McCarthy, and Green Party co-leader Caroline Lucas.