"Harry Potter" actress Emma Watson recently thrashed rumors that she will be part of the big screen adaptation of "50 Shades of Grey." The actress may not be ready to be part of this erotic movie, but she does not mind stripping down and posing for a good reason.

Pictures featuring Watson showing off her bare shoulders will be part of a new book "Natural Beauty," which will benefit Global Green USA.

The 22-year-old actress features in a series of photos with dramatic makeup and wet hair. The only accessories used in the photos are orchid flowers.

Watson tweeted the news along with a picture from the series saying, "My friend is supporting GlobalGreenUSA with his book Natural Beauty. It's out now. : ) X"

According to MTV News, New York-based photographer James Houston began shooting nude portraits of eco-conscious celebrities to promote awareness amongst young people. In a press release Houston explained what his aim is.

Click here to see more steamy pictures of Emma Watson.

He said: "This project merges my longtime interest in the human form and my passion for the natural world. 'Natural Beauty' was created to celebrate the beauty of nature, emphasizing what we still have versus what we have lost. I hope to raise environmental awareness among the younger audience through this project."

Brooke Shields, Christy Turlington, Elle Macpherson, Adrian Genier and Arizona Muse have also posed for the camera to help raise awareness through this 120-page book, which will be released later in spring. A 12 part web series showcasing the making of the book "Natural Beauty" will premiere on YouTube later this month.

Check out a sneak peek of behind the scenes footage of the "Natural Beauty" photo shoots below.

The photographer will also launch an exhibition of select images from the series at Milk Gallery in New York at the end of April, reported The New York Post.

In the meantime, Watson is set to surprise her fans in her next movie, Sofia Coppola's "The Bling Ring." This movie is based on a true story of young thieves who targeted celebrities like Paris Hilton, Lindsay Lohan and "The Hills" star Audrina Patridge.