The Queen's grand-daughter beat her cousin Princess Beatrice to the top title, according to the list compiled by Luton's millinery and hat-making industry.

She was joined in the top spot by Hollywood heartthrob Brad Pitt, who beat fashionable footballer David Beckham into second place.

This is the fourth year of the Celebrity Hat Wearers list, produced by promotional consortium Luton First with the town's 400-year-old hat-making trades.

This year's list also includes Paris Hilton, Sara Jessica Parker and Naomi Campbell, as well as Jude Law and George Clooney.

Joining his royal relatives in the top ten is Prince Harry, who also featured in last year's list. Zara Phillips was last featured in the 2005 chart.

Philip Wright, of Luton milliner Walter Wright Ltd, said: "We have the royal princesses and Kate Middleton waiting to take on Princess Diana's fashion crown but we are still waiting for a Royal male to show a positive style lead in all aspects of the male wardrobe."

Mr Wright said the top celebrities were wearing "statement" hats, which are fun and have something to say for themselves.

He added: "Zara has opted for the more masculine but highly-fashionable trilby and fedora hat styles, together with some of the neat, chic, 1920s-inspired designs.

"But she's also gone for some fairly extravagant styles which are both fashionable and fun."