The British drummer is in training for the 26.4 mile (42.2 kilometre) run in the U.K. capital in April (13) - and just weeks later he will take part in the Tough Mudder challenge, a 13 mile (20.9 kilometre) assault course designed by the Special Forces to test strength and stamina.
Judd has taken to his Twitter.com page to appeal for sponsorship cash, which will benefit The Teenage Cancer Trust and the Eyes Alight charity, which grants wishes for youngsters with brain injuries.
In a post on his page, he adds, "Please don't apologise for small donations. Any kind of donations (sic) is Hugely appreciated. Thank you."