Diehard Gossip Girl fans were quick to recognize the gorgeous Jenny Packham-designed evening gown Catherine Middleton wore to the ALK Gala in London last night. That's because Blair Waldorf (a.k.a. Leighton Meester) wore a similar look by the designer during season four. Both dresses are from the Packham's spring 2011 collection, and while the two looks are quite similar, they are not, in fact, the same. Catherine's gown, runway look #21, was a lighter rose pink shade and featured a distinct embellished waist, while Blair/Leighton's, runway look #26, was tea-length and had vertical stripes of sparkly shimmer. Who knew the Duchess and Miss Waldorf shared the same taste?