Strictly Come Dancing judge Craig Revel Horwood had the Duchess of Cornwall moving like a ballroom diva when he gave her an impromptu cha cha cha lesson in the West End.

The choreographer encouraged Camilla to wiggle her hips and move her feet to a Latin track when the pair visited a London school on World Osteoporosis Day.

Taking a twirl: Camilla joins Craig Revel Horwood for a dance

The Duchess and the celebrity dance instructor held hands and shimmied in the hall of St Clement Danes primary school which is taking part in a National Osteoporosis Society (NOS) project.

The school is one of six across the country receiving a visit from Revel Horwood after winning a competition where they had to prove their "bone health" credentials.

The royal, who is the NOS's president, watched the celebrity judge put a group of around 20 nine-year-olds through their paces. The youngsters are being encouraged to dance to help strengthen their bones and keep them active.

More pictures: Camilla dances with Craig Revel Horwood

The 44-year-old choreographer lived up to his straight talking reputation when he told the school children "timing is essential, you're all ahead of the beat," but ended by praising them as "fantastic".

He then turned to Camilla and took her hands as school governors and senior NOS staff watched laughing.

As the pair moved backwards and forwards the choreographer told the Duchess "now a little bit of hip action" and as she began to sway he gave her some encouragement, saying "that's fantastic".

Later the Strictly Come Dancing judge, who is an NOS patron, said: "I'd give her 10. She kept rhythm, her timing was excellent, her footwork was excellent - she has the personality for it."

The choreographer also defended his comments from the weekend's show where he compared contestant Jo Wood to "a bush kangaroo". The criticism prompted her dance partner Brendan Cole to storm off and a ticking off from show host Bruce Forsyth.