The 91-year-old monarch gave out the first Queen Elizabeth II Award for British Design on Tuesday to London-born Richard Quinn.
She sat next to American Vogue chief editor Anna Wintour in the front row.
The queen wore an Angela Kelly duck egg blue tweed dress and jacket detailed with tiny Swarovski crystals.
She also toured showrooms before presenting the award on the final day of fashion week.
Quinn established his label in 2016 after studying fashion at Central Saint Martins and has been widely recognized as one of Britain’s talented young designers