"The joke is that you start in the company playing Barnardo in the first act of Hamlet, then you graduate to play Rosencrantz and Guildenstern, then it’s Horatio, then maybe Laertes and possibly Hamlet. Then you start playing Claudius and then Polonius - and then you play the skull, though we’re not quite there yet." Sir Ian McKellen links the ages of the thespian to the characters in Shakespeare's classic Hamlet.