The Duke of Cambridge proved to the world he's got street credibility by creating a new dance tonight.
William was labelled "cool" by teenagers from a south London centre for homeless youngsters after coming up with the "Swag Dance".
The new moves involve brushing imaginary dust off your shoulders as your partner copies you - signalling you have trendy threads.
Kate was not to be outdone by her husband and also bonded with one disadvantaged teenager during a cookery class by making her a birthday cookie the young woman swore she would never eat.
Inspiration struck for the second-in-line to throne as he discussed his wedding outfit with the Duchess and a group of young women who are clients at Centrepoint's Camberwell Foyer - a home for troubled young people.
William, who as a Colonel of the Irish Guards wore the regiment's scarlet red tunic when he wed the Duchess in April, asked Vanessa Boateng, 18, about his uniform.
The teenager, a trainee nursery nurse who moved to the Foyer after family problems, said: "William asked us what we thought about what he wore to his wedding. He said, was his suit dapper?
"I said: 'No, your swag was on point.' He repeated my words and said 'swag', then he started doing this dance."
Later during a reception for many of the Foyer's 80 residents the royal called Miss Boateng over.
The Duke and the 18-year-old performed the dance for the cameras as everyone screamed and cheered - brushing their shoulders in unison.