Connery and Lynch
This film was pretty lighthearted and I'm sure it was intended to be.
Ne'ertheless it had a couple of serious bits, for instance where the Lynch character got sick in reaction to instinctively killing enemies, which he did not anticipate ever doing.
Connery was the consumate buffoon, who would have thought he was being cast as James Bond about then.
Only a few years later the two were together in "The Hill", a war/prison movie, nothing comic about it at all.
Lynch played a sad little guy who should never have been a soldier at all, imprisoned for trying to run away home. Connery a warrior type who had stuck his neck out to save his men.
These guys were real actors, who could play a range of parts.