Patalliro! (1982)

MI6 agent James Bancoran is assigned to the island kingdom of Malynera to protect its young ruler Prince Patalliro the Eighth. Malynera is located in the South Seas, and possesses an inexhaustible supply of diamonds; for this reason it is being constantly being targeted by an international syndicate who wants those diamonds. Bancoran is cool-blooded and charming and able to handle these perils as an elite secret agent... what he has trouble with is the young king, for Patalliro is a mischievous, lewd troublemaker who is guaranteed to cause devastation and disaster wherever he goes (especially with Bancoran's many lovers, both male and female). The harassed and hassled Bancoran must not only keep the young king and his domain from the syndicate, but must also protect the world from being wrecked by Patalliro!