The HELLO! Online blogger, who has openly voiced her disgust at people wearing real fur, posed naked as part of an advert to promote the campaign.
In the billboard, Lucy is pictured baring all, leaning back on a chaise longue and gazing seductively at the camera as her brunette locks cascade down her back. "Fur? I'd rather go naked," reads the statement on the PETA advert.
The reality star was spotted doing a photoshoot in London for the animal rights organisation and brought along her adorable pooch Digby for company.
"So, this happened," wrote Lucy to her 623,000 Twitter followers, alongside a photo of the duo. "I would rather go naked than wear fur! Take note people. @PETAUK."
"There is nothing glamorous about ripping fur off an animal's back whilst they are still alive so you can have a nice coat. Wear faux fur," she tweeted shortly after.
Lucy's advert was released on Thursday, with PETA's associated director Mimi Bekhechi previously stating, "Lucy understands that being sexy and glamorous is all about feeling confident in your own skin, not the skin of tortured animals.
"She is a great example for other young women and proves that you don't need to kill animals in order to have a killer look."
Other celebrities who have featured in PETA's campaign include Khloé Kardashian, Penélope Cruz, Pamela Anderson and Eva Mendes.