Shakespeare’s Twelfth Night is already famous for its gender and sex confusion without Malvolio having a sex change.

On the National Theatre’s poster there is a photograph of an elegant Tamsin Greig standing on a staircase in a smart suit, white shirt and high heels, and a bottle of champagne at her feet – so that is what I thought “Malvolia” might transform into after she had read Olivia’s love letter. Instead, Greig on stage is dressed in a Pierrot costume, which she throws off to reveal a showgirl striptease corset, and she bursts into song, as if she were a cabaret artiste. It is so over the top as to be totally unbelievable.