to the manner born

Coming naturally, as if accustomed from birth. She grew up in poverty, but since she became famous she has taken to rubbing shoulders with the upper crust as if to the manner born.

Accustomed from birth to a particular behavior or lifestyle, as in At a high-society function she behaves as though to the manner born, but we know she came from very humble circumstances . This term was invented by Shakespeare in Hamlet. Referring to the King's carousing in Danish style, Hamlet says (1:4): "Though I am native here And to the manner born, it is a custom More honor'd in the breach than the observance." The manner in this expression was later sometimes changed to manor, "the main house of an estate," and the idiom's sense became equated with "high-born" (and therefore accustomed to luxury), a way in which it is often used today.

Accustomed to a position, custom, or lifestyle from or as if from birth.

Familiar with such things. The phrase comes from Hamlet: “But to my mind, though I am native here. And to the manner born, it is a custom / More honour'd in the breach than the observance.” The widespread confusion between “manner and “manor” has been going on for at least two centuries. “To the manor born,” in the sense of accustomed to luxury as if raised in an aristocratic environment, was used as the title of a British sitcom that achieved some popularity on American public television.