Harry Hamlin as Perseus Judi Bowker as Andromeda Burgess Meredith as Ammon Maggie Smith as Thetis Siân Phillips as Cassiopeia Claire Bloom as Hera Ursula Andress as Aphrodite Laurence Olivier as Zeus Pat Roach as Hephaestus Susan Fleetwood as Athena Tim Pigott-Smith as Thallo Jack Gwillim as Poseidon Neil McCarthy as Calibos Vida Taylor as Danaë Donald Houston as Acrisius Flora Robson, Anna Manahan and Freda Jackson as the Stygian Witches