He saw the apparition while performing Waiting for Godot with Sir Ian McKellen.
Stage hands believe he saw the ghost of John Baldwin Buckstone, who was actor-manager of the Theatre Royal Haymarket in the mid 19th century and a friend of Charles Dickens.
Patrick Stewart Upon coming offstage for the interval, Stewart told his co-star that he saw a man standing in the wings wearing what looked like a beige coat and twill trousers.
Sir Ian asked him: “What happened, what threw you?”
“I just saw a ghost. On stage, during Act One,” Stewart replied.