Camilla, the Duchess of Cornwall, has told Lady Gaga they share the same nickname.
The 69-year-old royal met the singing sensation at the Royal Variety Performance at London's Hammersmith Apollo last night (06.12.16), and greeted her by saying her grandchildren - Prince George, three, and 19-month-old Princess Charlotte - call her the same as the 'Bad Romance' hitmaker.
She said: "My grandchildren call me Gaga."
Camilla and Prince Charles met several stars at the spectacle, including singer Robbie Williams and host David Walliams, who couldn't resist poking fun at the pair.
As he led a group of people up to the royal box he asked the couple: "Can I see your tickets please?"
He then turned back to the group and quipped: "There's some riff-raff here sitting in your seats."
While Charles and Camilla appeared to be enjoying themselves as they met celebs on the red carpet, the 68-year-old prince is not a big fan of the Royal Variety Performance.
Comedian Michael McIntyre recently revealed he asked the Prince of Wales about the annual entertainment bash - which was set up to raise money for the Royal Variety Charity - and the royal admitted he disliked the event.
Michael explained: "I said to Prince Charles 'Do you like the Royal Variety' and he just went 'No. Sorry, I probably shouldn't have said that.' "