The unnamed man sustained an injury while acting out a sword fight reportedly involving Branagh during a stage production of the show at a deconsecrated Victorian church in Manchester, England.
The actor, who is said to have been struck with a metal sword, played through the pain to complete his turn on stage, but was taken to hospital after the curtain came down.
The production is part of the Manchester International Festival, and a spokesman for the event confirmed the injured actor was not seriously hurt, telling Britain's Daily Mail, "An actor was hurt during one of the fight scenes in a performance of MACbeth on Wednesday night. We have qualified medics on site during each performance and the actor was assessed and told he was fine to continue with the evening's performance."
Branagh previously said of the play's fight scenes, "There is enormous concentration (needed)... It is impossible to say that it is without danger. Metal clashes, sparks literally fly."
Actors are notoriously superstitious about appearing in MACbeth and many refuse to refer to the dark tragedy by name, calling it 'The Scottish Play' amid fears of a jinx.