There can only be 24 living people in the order at any given time , not including honorary appointees , and new members are personally selected by the reigning monarch of the 16 realms , presently Queen Elizabeth II , with the assistance of her private secretaries ; the order has thus been described as `` quite possibly , the most prestigious honor one can receive on planet Earth . '' There may be , however , only 24 living individuals in the order at any given time , not including honorary appointees , and new members are personally selected by the reigning monarch of the 16 realms , presently Queen Elizabeth II , with the assistance of her private secretaries ; the order has thus been described as `` quite possibly , the most prestigious honor one can receive on planet Earth . ''