Kate Middleton wore many dresses in 2011, but the most famous was her long-sleeved lace wedding gown viewed by millions worldwide.

The second most-famous might have been the navy lace sheath by Erdem, worn at the start of Catherine and William's royal tour through Canada and California.

It seems that those two dresses scored such high marks that Kate's taken the lacy style for a third go-round. On the eve of her 30th birthday, she and Prince William walked the red carpet at today's "War Horse" premiere in London, with the duchess wearing a black gown designed by a Pippa Middleton favorite, Alice Temperley.

Similar to her wedding gown and Erdem dress, the Temperley frock had sheer sleeves and a lined bodice, as well as 3/4 length sleeves and a sexy v-neck. With flattering seams running horizontally and vertically across the dress, Kate's gown highlighted her slender figure -- and distinct lack of baby bump, for those keeping track.

Also in the spirit of "if it ain't broke, don't fix it," the duchess wore her enviable tresses (recently named the most coveted celebrity hair style) long and loose. On the accessories front, she sported diamond drop earrings, a diamond bracelet and a simple black clutch.

There was also a fancy umbrella involved, carried by doting husband Prince William (who, for the record, wore his typical large-lapel tuxedo).

The Temperley dress is a far sexier style than Catherine's worn in the past -- if her lavender Alexander McQueen dress from the royal tour said "princess," this dress screams "on-screen siren."

And we're definitely liking it.

Check out the Duke and the Duchess of Cambridge on the red carpet -- do you dig Kate's new look?