Runner-up in the Cesarewitch on the Flat, he showed his improvement had continued over obstacles by winning the Elite Hurdle at Wincanton on Saturday in clear-cut fashion.
Williams had been weighing up his options, with a big handicap at Ascot also under consideration, but he has decided to strike while the iron is hot.
The in-form handler, who also won the November Handicap at Doncaster with Saunter last weekend, tweeted: "After careful consideration, I've decided that London Prize will run in the @unibet @GreatwoodHorses Hurdle @CheltenhamRaces on Sunday - he's come out of his Wincanton race in great form."