Pasquale, who follows in the footsteps of recent King Arthurs Stephen Tompkinson, Jon Culshaw and Marcus Brigstocke, will play the role at the Playhouse Theatre from 17 June 2013 for a six week run.
No stranger to the musical stage, Pasquale has previously appeared in the touring productions of Mel Brooks' The Producers, The Wizard of Oz and Tom Stoppard's Rosencrantz and Guildenstern Are Dead.
As well as numerous live stand up shows he has appeared in six Royal Variety Performances and won the fourth series of I'm a Celebrity... Get Me Out Of Here!.
Bonnie Langford (Cats, Gypsy, Chicago) continues as The Lady of The Lake.
"I've known Bonnie Langford since we worked together doing Peter Pan in 2000", Pasquale said. "The Spamalot Knights recently strong-armed Bonnie into joining twitter and she amassed over 1,000 followers in her first week. When I saw she had joined up I sent her a message to welcome her as we'd lost touch for years.
"She invited me to see the show and I loved it so much that I went backstage afterwards to congratulate the cast. It was then that Bonnie said she thought I'd make a great King Arthur and the next thing that I knew, the show's producers spoke to my agent and it went from there very quickly."
Spamalot producers have also announced a new summer performance schedule, starting on 1 July 2013, which will include two shows on Fridays.