The stars descended on the U.K. capital's Somerset House, where Blow's outlandish outfits are on display.
The collection was purchased by socialite Daphne Guinness after the style icon's suicide in 2007, and heavily features pieces by her protegee Alexander MCQueen, who also took his own life in 2010.
Guinness says, "The decision to put Isabella's wardrobe on display was a natural progression; it felt like what she would have wanted. I bought the collection because I couldn't bear for it to be dispersed; it was her life's work - her legacy. What better way of celebrating that legacy than allowing the world to view it?"
British royal Princess Beatrice, designer Jasper Conran, model Liberty Ross and Bond girl Gemma Arterton also attended the glamorous launch event. The exhibition runs until March (14).