Prince William insisted he took his royal duties "seriously" but complained they can "weigh you down" in a rare interview out on Wednesday following claims that he is slacking off on official engagements. "I take duty very seriously. I take my responsibilities very seriously," he told the BBC in an interview broadcast ahead of his grandmother Queen Elizabeth II's 90th birthday on Thursday. "But it's about finding your own way at the right time and if you're not careful, duty can sort of weigh you down an awful lot at a very early age and I think you've got to develop into the duty role," he said. The second in line to the throne after his father Prince Charles said the queen was "a real guiding example of just what a good monarch could be." The Sun, Britain's most widely-read newspaper, in February dubbed William the "reluctant royal" after noting he had conducted just 122 official engagements last year, while the queen had carried out 341. Official photographs of the prince and his family skiing just weeks later fueled the growing criticism, with The Sun's headline reading: "Sloping off again... Workshy Wills takes family skiing." "I'm going to get plenty of criticism over my lifetime. It's not something I completely ignore but it's not something I take completely to heart," the prince said in the BBC interview. — Agencies