Howard Panter for the Ambassador Theatre Group presents the updated show, directed by Christopher Luscombe, at the Harold Pinter Theatre from Tuesday, July 24 to Sunday, September 9.
Eric Idle, who wrote the production with John Du Prez, will appear each night as a filmed recording playing God.
Marcus Brigstocke will play King Arthur from July 24 to August 1. Jon Culshaw replaces him in the role from August 2 to September 2, before Brigstocke returns from September 4 to 8.
Tickets for the play are priced from £15 to £65 and are on sale now.
Idle "lovingly ripped off" 1975 film Monty Python and the Holy Grail to create the production.
He and his former Monty Python partner John Cleese had a spat last December regarding royalties from the play after Cleese's voice was cut from the show.
Spamalot closed on Broadway in 2009 after winning several Tony awards and grossing over $175 million (£113 million).
Watch an advert for the last US run of Monty Python's Spamalot below: