LONDON, ENGLAND - JULY 12: Camilla, Duchess of Cornwall chats with photographer Don McCullin as she hosts the 30th Anniversary Garden Party for the National Osteoporosis Society in St James Palace on July 12, 2016 in London, England. Due to inclement weather the event was moved indoors. The Duchess of Cornwall has been connected with the charity for nearly 30 years. (Photo by Chris Jackson/Getty Images)

LONDON, ENGLAND - JULY 12: Camilla, Duchess of Cornwall chats with photographer Don McCullin as she hosts the 30th Anniversary Garden Party for the National Osteoporosis Society in St James Palace on July 12, 2016 in London, England. Due to inclement weather the event was moved indoors. The Duchess of Cornwall has been connected with the charity for nearly 30 years. (Photo by Chris Jackson/Getty Images)

LONDON, ENGLAND - JULY 12: Camilla, Duchess of Cornwall shares a joke with Richard E Grant and Miriam Margolyes as she hosts the 30th Anniversary Garden Party for the National Osteoporosis Society in St James Palace on July 12, 2016 in London, England. Due to inclement weather the event was moved indoors. The Duchess of Cornwall has been connected with the charity for nearly 30 years. (Photo by Chris Jackson/Getty Images)

LONDON, ENGLAND - JULY 12: Camilla, Duchess of Cornwall is presented with some customised (Orange laces for 'lace up for bones') Dubarry Boots as she hosts the 30th Anniversary Garden Party for the National Osteoporosis Society in St James Palace on July 12, 2016 in London, England. Due to inclement weather the event was moved indoors. The Duchess of Cornwall has been connected with the charity for nearly 30 years. (Photo by Chris Jackson/Getty Images)

LONDON, ENGLAND - JULY 12: Camilla, Duchess of Cornwall is presented with some customised (Orange laces for 'lace up for bones') Dubarry Boots as she hosts the 30th Anniversary Garden Party for the National Osteoporosis Society in St James Palace on July 12, 2016 in London, England. Due to inclement weather the event was moved indoors. The Duchess of Cornwall has been connected with the charity for nearly 30 years. (Photo by Chris Jackson/Getty Images)

LONDON, ENGLAND - JULY 12: Camilla, Duchess of Cornwall with Professor David Marsh and CE of NOS Claire Severgnini as she presents the Professor with the Duchess of Cornwall Award for OUtstanding Contribution to the field of Osteoporosis as she hosts the 30th Anniversary Gigarden Party for the National Osteoporosis Society in St James Palace on July 12, 2016 in London, England. Due to inclement weather the event was moved indoors. The Duchess of Cornwall has been connected with the charity for nearly 30 years. (Photo by Chris Jackson/Getty Images)

LONDON, ENGLAND - JULY 12: Camilla, Duchess of Cornwall laughs with her daughter Laura Lopes as she hosts the 30th Anniversary Garden Party for the National Osteoporosis Society in St James Palace on July 12, 2016 in London, England. Due to inclement weather the event was moved indoors. The Duchess of Cornwall has been connected with the charity for nearly 30 years. (Photo by Chris Jackson/Getty Images)

LONDON, ENGLAND - JULY 12: Camilla, Duchess of Cornwall talks to Kathy Lette and Jenni Murray as she hosts the 30th Anniversary Garden Party for the National Osteoporosis Society in St James Palace on July 12, 2016 in London, England. Due to inclement weather the event was moved indoors. The Duchess of Cornwall has been connected with the charity for nearly 30 years. (Photo by Chris Jackson/Getty Images)