See what the Duchess of Cornwall told Lady Gaga they had in common!

The Duchess of Cornwall and Lady Gaga at the Royal Variety Performance on Tuesday.

The Duchess of Cornwall told the singer her grandchildren call her "Gaga".

Camilla exuded heaps of glamour in a heavily embellished red lace gown.

The royal couple were also introduced to Robbie Williams and host David Walliams before the star-studded show, which was held at the iconic Hammersmith Apollo.

Ahead of the event, David said: "I'm very honoured and excited to be hosting the Royal Variety Performance. I was lucky enough to host back in 2012 so will be looking forward to another fabulous evening with huge talent."

Sting performed his hit Every Breath You Take on the night.