Emma Watson will strip down to raise environmental awareness, even though she won’t do it for the ‘Fifty Shades of Grey’ movie.

‘The Perks of Being a Wallflower’ star tweeted her support for James Houston’s book of celebrities posing nude to raise environmental awareness. The book’s proceeds will go to Global Green USA, a non-profit focused on sustainability.

“My friend is supporting GlobalGreenUSA with his book ‘Natural Beauty’. It’s out now. :),” she wrote on Twitter, posting a bare-shouldered portrait of herself.

In the book, the 22-year-old poses in various states of undress, covering her breasts with her arms or boldly hued flowers. She’s all balmy and sophisticated, whichs leads us to a less-than-sophisticated S&M rumour.

Earlier this week, she put an end to reports that she would be taking on the starring role in the bondage-based ‘Fifty Shades of Grey’ film.

“Who here actually thinks I would do 50 Shades of Grey as a movie? Like really. For real. In real life?” Watson tweeted on Saturday.

Sustainability: 1. Red Room of Pain: 0.

Back to the book... “This project merges my longtime interest in the human form and my passion for the natural world,” said Houston, a New York-based photographer. “Natural Beauty was created to celebrate the beauty of nature, emphasising what we still have versus what we have lost. I hope to raise environmental awareness among the younger audience through this project.”

Some of the portraits will be on show at New York’s Milk Gallery in April, and a 12-part web series that documents the making of the book will hit YouTube on Monday. Other celebrities featured in ‘Natural Beauty’ include Adrian Grenier, Christie Turlington, Elle MacPherson and Brooke Shields.