Role-playing on stage, e.g. an actor playing Shakespeare’s Richard III, clearly differs from role-playing in real life, e.g. Richard III playing that role in 15th century London. On-stage acting has been distinguished from real-life acting in various ways: as involving ‘make-believe’, with audiences having to ‘suspend their disbelief’ (e.g. that they are watching Richard III); or ‘pretence’ (the actor pretends to be Richard III); or ‘imitation’ (the actor imitates Richard III). I argue that none of these will do, and that on-stage acting is just a special kind of representation. That is, actors represent the characters they play, not by describing them, as the text of a novel, history book, or screenplay does, but by depicting them, as still pictures or CGI animations of them do. But in stage (or screen) acting, unlike these other methods of depiction, real or fictional people (the characters) are being depicted by other people (the actors). This requires actors to use some of their own attributes (voice, appearance, etc.), adapted as required (by costume, makeup, etc.), to depict those of their characters. That is why actors often say they try to become the characters they play, why great performances are so hard to achieve, and why great parts (Richard III, Hamlet, Othello) can be played equally well but very differently by different actors.