Kate Middleton and Prince William sat in the royal box for the Royal Variety Performance in 2014, which allowed Jack Whitehall to see the “sharp look” the Duke threw him after his cheeky comment

As well as both being very, very posh, the Duchess of Cambridge and Jack Whitehall have another thing in common – their school.

They both attended the private boarding school Marlborough College, but Kate was a few years older than the comedian.

Jack brought up their shared education at the Royal Variety Performance in 2014, but he also used the occasion to reveal an “inappropriate” secret.

As Jack took to the stage to huge cheers from the crowd, he explained how he knows Kate.

He said: “I’m very excited to be here. I’m especially excited to be here performing in front of the Duchess of Cambridge.