Credit: Samir Hussein/WireImage.com

Duchess Kate is looking teeny-tiny!

The 29-year-old royal showed off her minuscule waist Wednesday during a visit to Centrepoint's Camberwell Foyer to bring cheer to young homeless people. Looking casual next to hubby Prince William, Kate stunned in an olive green turtleneck dress belted primly at her midsection.

Kate's wool and cashmere frock was much more casual than the elegant black velvet Alexander McQueen for the Sun Military Awards in London on Saturday. Royal fans were instantly reminded of a similar dress the late Princess Diana wore to the White House in November 1985, where she danced with John Travolta.

William, also 29, opted for a low-key look Wednesday as well. Ditching his usual suit, the prince donned blue corduroys and a nice shirt, but no tie. See more pics of the couple at Wednesday's event.

In the kitchen of the south London homeless center, a source tells Us Weekly the couple put on white Centrepoint aprons and started making mince pies. They also decorated "gingerbread biscuits" (cookies) with some of the youth.

Kate joked to William, "Does this mean you're going to make me mince pies when we get back [home]?" and he chuckled.

William has been a patron of Centrepoint since 2005.