The actor James Phelps, who starred as 'Fred Weasley' in the Harry Potter film franchise, has turned a surprise trip to London into a magical experience for a young family of Harry Potter fans.

The Johnson family, from Los Angeles, California, received the once-in-a-lifetime trip to London, and a one-off VIP tour of Warner Bros. Studio Tour London -- The Making of Harry Potter with James Phelps, after the city's official tourism body, Visitlondon.com identified them as genuine 'super fans' of Harry Potter.

Fans of London -- devised by Visitlondon.com, celebrates the blockbuster events across London this year including The Queen's 90th birthday celebrations, 400 years of Shakespeare's legacy, and the world's first exhibition on the Rolling Stones, EXHIBITIONISM.

The Johnson family were selected by Visitlondon.com after an extensive search across the US.

Adam (11), Daniel (13), and Victoria Johnson (14), who had never left the United States before their visit to London, have been avid Harry Potter fans for years. "My mum used to read the books to me and my brother and sister even before we were born," said Harry Potter super fan, Adam Johnson. "When I think of Harry Potter I always think of London. Our trip was so much fun, especially meeting James Phelps -- and I really wish I had a real life Firebolt broomstick so that I can fly back to London whenever I want!"

The family also run a successful LA-based charity that helps local children overcome bullying.

James Phelps surprised the Johnson children at the home of the film series, Warner Bros. Studio Tour London -- The Making of Harry Potter, which is celebrating the 15th anniversary of the UK release of Harry Potter and The Philosophers Stone this year.