Most 18 year olds might spend the year between high school and university on a working holiday or getting some post-exam R&R, but not Emma Watson.

The Harry Potter star, now 19, spent five months in the role of Creative Advisor.

At UK label People Tree to create a capsule collection made of 100 per cent organic and Fair Trade cotton.

"It has been the most incredible gap year project," said the actress in a statement.

Pieces in the collection include slogan jersey T-shirts, cropped tracksuit pants and nautical-stripe T-shirt dresses that wouldn't be out of place on the campus of Watson's American college, Brown University.

"I think young people like me are becoming increasingly aware of the humanitarian issues surrounding fast fashion and want to make good choices but there aren't many options out there," she says.