While "Harry Potter" author J.K. Rowling is busy knocking down a mansion to expand her personal garden, two stars from the films based on her books have been climbing mountains for charities — no magic spells required. 

James and Oliver Phelps recently climbed the highest peaks in Scotland, England and Wales in a 24-hour stretch to raise cash for two charities: the Royal National Lifeboat Institution and the Great Ormond Street Hospital Children's Charity. The brothers have played the roles of practical jokers Fred and George Weasley in the "Harry Potter" film series since the franchise hit theaters in 2001.

"The pride and relief was amazing in completing the three peaks and it was a very rewarding experience," said Oliver, who hopes to help fund lifeguards at a place where he regularly surfs. "My stamina is higher than I thought it could be. The great support that I received from everybody kept me going, so huge thanks go to all."

According to LooktotheStars.org, James became inspired to raise cash for the Great Ormond Street Hospital Children's Charity after a first-time visit earlier this year.

"And it is a day I will never forget," he said. "Not only did I see how hard-working all of the staff there are, but how amazing the children in there are also. Even for some, fighting life-threatening illnesses, their attitude and determination was something that I will always remember."

The three peaks climbed included the Ben Nevis in Scotland (4,409 feet), Scafell Pike in England (3,209 feet) and Snowdon in Wales (3,560 feet).

Also on MNN: 10 real-life ways muggles can experience Harry Potter

Michael d'Estries ( @michaeldestries ) covers science, technology, art, and the beautiful, unusual corners of our incredible world.

'Harry Potter' twins climb mountains for charity
James and Oliver Phelps scoured the highest peaks in Scotland, England and Wales within 24 hours.