Davison plays King Arthur on a comedic quest for the Holy Grail

The 56-year-old, also known for his role as Tristan Farnon in All Creatures Great and Small, replaces Shakespearean actor Simon Russell Beale from 23 July.

Coronation Street's Charlie Stubbs - aka actor Bill Ward - will also join the stage show's cast as Sir Lancelot.

The musical, based on Monty Python's 1975 Holy Grail film, has won three Tony Awards on Broadway.

The UK production was nominated for seven Laurence Olivier theatre awards this year, but failed to win any trophies.

Brian musical

Loosely based on the legend of King Arthur, Spamalot features flatulent Frenchmen, a legless knight and a killer rabbit.

It was written by former Python Eric Idle, who recently unveiled his next project - Not The Messiah (He's A Very Naughty Boy) at Toronto's Luminato festival.

The oratorio is based on the comedy troupe's Life of Brian film, which tells the story of Brian Cohen, a young man born on the same night and the same street as Jesus Christ.

An hour-long preview showcased some of the songs written for the new musical - including Hail To The Shoe and Brian's Dream - by Idle and composer John DuPrez.