The 14 Most Outrageous Celebrity Hats

Princess Beatrice made headlines when she wore an intricate structured beige design by Philip Treacy to Prince William and Kate Middleton's royal wedding. The look launched over 40 Facebook groups before fetching over $130,000 in an online auction to benefit charities for children.

Aretha Franklin made history when she sang "My Country, Tis of Thee" at President Obama's inauguration wearing a bow-topped hat. The $179 style, customized with Swarovski crystals, came from Mr. Song Millinery in Detroit where Luke Song has been making hats for 28 years.

The actress went the nature route at the 2008 premiere of Sex and the City in this green floral-and-acorn Philip Treacy creation.

Madonna scored big with her halftime show during this year's Super Bowl. The Material Girl took the stage in front of an audience of 111.3 million wearing a gold headdress by Philip Treacy -- perfect for her Egyptian-themed opening dance number.

Parker wore a spiraling Philip Treacy design to a Melbourne luncheon in honor of Oaks Day, Australia's version of the Kentucky Derby in November 2011.

At the 2011 Kentucky Derby, Paula Patton wore a hat for Grey Goose vodka designed by milliner Louise Green.

Katy Perry made an appearance at the 2011 MTV Video Music Awards in a yellow Christian Dior cube hat.

Lady Gaga loves a good fascinator! The pop star strolled the streets of London in a twisty hot pink design.

Lady Gaga brought some futuristic style to the 2010 Grammys with her towering geometric Philip Treacy topper.

Demi Moore topped off her feathered Prabal Gurung gown with a spiky black Philip Treacy headpiece at the 2011 Met Gala.