Pirates of the Caribbean

Disney may be going au naturale for Pirates of the Caribbean: On Stranger Tides.

The movie studio has banned actresses with artificial enhancements for the fourth Pirates installment, the New York Post reports.

Johnny Depp back for new Pirates of the Caribbean movie

Filmmakers sent out a casting call last week, according to the paper, seeking "beautiful female fit models. Must be 5 feet 7 inches-5 feet 8 inches, size 4 or 6, no bigger or smaller. Age 18-25. Must have a lean dancer body. Must have real breasts. Do not submit if you have implants." The potential ladies will also have to undergo a test involving jiggling and jogging to determine their breasts' authenticity, the Post says.

The movie, which is set for a May 2011 release, will star Johnny Depp as Jack Sparrow, Ian McShane as Blackbeard, and Penelope Cruz as Sparrow's love interest, replacing Keira Knightley as the female lead.