Public understudy performances (PUP's) are a rare treat. Most understudy runs are for invited friends and family only but the RSC opens their doors to the public in Stratford and now in London too, while in residence at the Barbican with Henry IV.
For those on a tight budget they are of course a cheap way of seeing an excellent production, all tickets are £10 and you get the same show just with a slightly different cast.
And although the lead actors have been substituted it doesn't necessarily mean you'll miss out on seeing them. At the understudy run for Henry IV part 1 last week, Jasper Britton who plays the King ended up understudying himself as his understudy was injured. No irony there but OK, so that is the exception, but we did get to see Alex Hassell who normally plays Prince Hal and Paola Dionisotti who normally plays Mistress Quickly who snuck into the crowd of customers during the tavern scene.
Of course if you haven't seen the production with the regular cast you may not notice them but if you have it adds a frisson of excitement, to see Prince and understudy Prince acting together - Sam Marks in this instance.
There is a lot of doubling up for the smaller parts so you also get to see some very fast changes and actors seamlessly switching roles. You may well see an actor leaving the stage as one character only to reappear moments later wearing a different hat and coat as another.
During Henry one actor even swapped hats as he was walking from one side of the stage to the other. It was subtly done so that if you weren't looking closely you'd probably not even notice. It's all part of the fun.
You could almost feel the audiences sit up when they realised that in the Glendower scene Leigh Quinn was going to be playing both Lady Mortimer and Hotspur's wife. How would it be handled? With some adjustments to blocking and a bit of imagination it worked beautifully.
It is all stuff you will only ever see in an understudy run and with many family and friends in the audience it is a performance propelled by good luck and wishes. Go and see one if you haven't before, if nothing else you'll get to enjoy some subtle differences in performances and interpretation from the main production.
Henry IV part 2 PUP is on January 8.