 During filming, actor Phil Silvers (qv) locked himself in his  trailer and refused to come out. Director Richard Lester (qv)  asked Jon Pertwee (qv) to step into the role of Lycus, as he  already knew the part after performing it on stage. Once Silvers  heard he had been replaced, he came out of his trailer, bursting  with new enthusiasm for the project. Pertwee was given the (much)  smaller role of Crassus as compensation.