The Duke and Duchess of Cambridge donned their black-tie best on Thursday evening to celebrate the university where they kindled their relationship.

The royal couple attended a charity dinner in London to support the University of St Andrews’s 600th anniversary appeal.

For Kate, the event provided a chance to re-wear one of her most elegant red-carpet gowns: a long-sleeved, black lace design, previously worn to the premiere of in January 2012. Tonight, she completed the look with a red clutch and poppy pin.

Although William is the official patron of the 600th anniversary appeal (launched to help disadvantaged students access education at the prestigious university), we suspect that Kate may prove its most valuable supporter. Can you imagine any better advertisement for the benefits of pursuing an art history degree at St Andrews than a beloved duchess?

Revisit Kate’s best looks in our Style File