The Prince of Wales has been revealed as a talented mimic whose dramatic readings of the Harry Potter books leave children spellbound.The Duchess of Cornwall said the future monarch is a “brilliant” impressionist and puts on voices for every character when reading the series to her grandchildren.In a conversation reported by the Daily Mail, Camilla provided a rare insight into the relationship the royals share with their young relatives.A grandmother of five, she said the couple relished spending time with their family.Speaking at a recent literacy event for children, she told the paper: “Sometimes, when we are with my husband in Scotland, he reads them Harry Potter.”And he does all the voices, because he is a brilliant mimic. I’m not very good. I try to do the voices, but acting isn’t my forte. But he sits down and they all sit with him.”I always think they are going to be wriggling around in the bed, but they sit spellbound.”She added: “He’s extremely good with children. They love it.” “Doing this latest assignment to celebrate Her Royal Highness’s 70th birthday is a true honour.”Testino was one of hundreds of guests at a Clarence House garden party on Thursday for the Duchess to acknowledge the people she works with, from charity bosses to celebrities. The royal couple were captured by celebrity photographer Mario Testino looking relaxed, happy and smiling.They were photographed in May in the morning room at Clarence House, with the Duchess wearing a navy blue dress coat with white embroidery by Fiona Clare, while the Prince wears a suit, shirt and tie. Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings. Camilla celebrates her 70th birthday on Monday, an occasion which has been marked by the release of an official portrait of her and Charles. Testino paid tribute to the Duchess, describing her as a “beautiful person”.He was Diana, Princess of Wales’s favourite photographer, has taken pictures of the Prince and his sons – the Duke of Cambridge and Prince Harry – several times, and photographed Charles and Camilla to mark their first wedding anniversary in 2006.The photographer said: “I’m honoured to document their royal highnesses the Prince of Wales and the Duchess of Cornwall on this very important date.”I first photographed the Duchess after her wedding to the Prince on a commission from British Vogue in 2006, and discovered a kind and beautiful person with a wonderful sense of humour.