The Princess wore a stylish houndstooth coat by Parisian fashion brand Sandro but it was the dress underneath which caught the attention of royal style watchers.
Fans are loving the flattering fit of the 'little black dress' which has received rave reviews online.
Eugenie styled her short brunette tresses in a pretty curled bob with an exaggerated side parting.
The newly married Princess kept her makeup to a minimum letting her radiant complexion shine through.
Her outing comes amidst mounting speculation that Eugenie and Jack are expecting their first child.
The younger Princess of York was seen chatting animatedly with guests as she fondly surveyed her wedding dress.
Eugenie's evening reception gown - a high neck, long sleeved blush piece designed by Zac Posen - was also on display.
The fashion exhibition, titled A Royal Wedding: HRH Princess Eugenie and Mr Jack Brooksbank, features the couple's formal outfits from their nuptials at St Windsor Chapel and runs until April 22.
This article originally appeared in New Idea.