John Rhys-Davies was also in a similar film - Indiana Jones and the Raiders of the Lost Ark (1981) - where he helps out with the archaeology work in the pyramids and goes inside one just like he does in Prisoners of the Sun (2013).
This was in various development stages a new version of "The Mummy" with Richard Donner involved. But with studio politics and Richard going off and doing other projects it went into limbo. Eventually got made and just got turned into this