The Harry Potter star shed her clothes to shoot a racy picture for the Blue Marine Foundation as part of the organisation's drive to protect the world's waters from over-fishing.

On Wednesday (18Mar15), the U.K.'s Chancellor George Osborne unveiled plans to create a marine life reserve around the Pitcairn Islands, a British territory in the South Pacific, and Bonham Carter is thrilled that her campaigning appears to have worked.

She says, "I never knew taking my clothes off could be so effective. I must do it more often."