What a dress! Heidi Klum shows off her growing belly — and a bit of leg! — at the 2009 Met Costume Gala, held Monday night in New York City.

With this year’s theme being “Model as Muse,” we think the catwalker fit right in!

We hope Heidi, 35, remembered everything she needed for the big night — she’s been suffering from a case of “pregnancy brain freeze,” she recently told Ellen DeGeneres.

“I don’t know what it is, I always forget things,” she admits. “It’s always like, the words…where are they? I know they were there before, where are they now? Like, where am I again?”

The baby, Heidi’s fourth, is due in October.