Prince William spoke for both him and Kate Middleton when he addressed crowds gathered in St Andrews university quadrangle.
"This is a very special moment for Catherine and me. It feels like coming home," he said.
The institution holds many fond memories for the couple, who began their romance there.
The Prince gave a speech about what he deemed "the best university in the world" before unveiling a plaque to mark the institution's 600th anniversary.
"Here's to 600 more years," he said.
There was also a chance for a trip down memory lane when the couple paid a private visit to university residence St Salvator's hall.
They both stayed there as first year students.
Photo: © PA