But the design is so classic that it's super easy to find without resorting to dropping major cash for the Tom Ford original!
We found two equally affordable options that are super similar to Kate's dress.
Check 'em out ...AFTER THE JUMP!!!
Dang, Sienna Miller's bod bounced back quick from her pregnancy!
The Girl actress hit up the Variety Performers Brunch at Nick & Toni in East Hampton New York on Sunday, and even though she just gave birth to her baby in July, she's looking as slim as ever!!!
For her skinny debut, Sienna rocked silk patterned Sea New York slacks, a crisp white button down top, a blue sweater, red ballerina flats and some retro sunnies.
Not only does she look great, she looks so chic, too!
What do U think?!?
[Image via Jason Kempin/Getty Images.]