Dirty Ho (1979)

Prince Wang is the 11th prince of Manchuria and an excellent martial artist, but prefers not to draw attention to himself and keeps a low profile, posing as a merchant who deals in wine, antiques, and paintings. He has a run-in with Ho Jen, a simple thief who makes a living by stealing and spending loot wherever he can. The Prince takes a liking to the thief and enlists him to be his bodyguard, something Ho takes to very reluctantly at first. But when a conspiracy unfolds and the Prince is targeted for assassination, Ho must undertake a serious training regime to protect his master.