The connection came to light when the 'prop' was revealed to be a genuine picture of an actor who achieved great fame in his time.

The large framed photograph of actor, theatre manager and producer Fred Terry - brother of Dame Ellen Terry - had been in the storeroom at Theatr Colwyn, Colwyn Bay, for many years and staff thought it was a prop from a past play.

Recently the photo was taken out of storage to be looked at in detail and a visitor pointed out that far from being a prop, it was something of significant importance to the theatre's long history.

It came to light that the man in the photo, dressed in stage costume, was Fred Terry, first person to play The Scarlet Pimpernel on stage. One of the first modern stars of the British stage, he was known as 'The Queen of Theatre'.

On the photograph is a dedication to Stanley Ravenscroft, who led the highly successful repertory company at Theatr Colwyn during the 1930s, 40s and 50s and actually lived at the theatre during his time as the company's director.

The dedication was written by Julia Neilson, wife of Fred Terry and a famous actress in her own right, having appeared in countless stage plays on the West End and in New York, including the first production of Oscar Wilde's An Ideal Husband.

Now Sotheby's auction house has been called in to value the image and find out who the photographer was.

A Theatr Colwyn spokesperson said: "Finding out that the photograph was real, not a prop, and that it had been given to Stanley Ravenscroft, by actors of such fame, has created much excitement at the theatre.

"We know very little about Mr Ravenscroft, other than that under his leadership the repertory company was incredibly successful, that he was a stage actor in his youth, and that he lived in a flat in the theatre for many years.

"Unfortunately, there are no clues as to how he knew Fred Terry and Julia Neilson, although the dedication does mention 'just for remembrance' so maybe they worked together at some point or were friends.

"We hope that Sotheby's will be able to help us in finding out a bit more about the photograph, it would be nice to discover what exactly the connection was between Mr Ravenscroft and Fred Terry."

Fred Terry, great-uncle to the legendary stage actor Sir John Gielgud, was very famous during the late 19th Century and early 20th Century.

He and his wife adapted the manuscript of The Scarlet Pimpernel for the stage and he was the first person to play the title role in a play that premiered in 1905 at The Strand Theatre, London.

Terry also appeared on Broadway several times with Julia, as well as managing and taking seasons at West End theatres in London, including The New (now The Noel Coward), The Strand (now The Novello) and The Haymarket.

He made international headlines during the First World War, when, during a performance of The Scarlet Pimpernel at the Strand theatre, 19 bombs were dropped by a German zeppelin on the road outside the venue, with one exploding in the main entrance causing plaster to fall on the heads of the performers and the audience.

Appearing in the lead role of Sir Percy Blakeney, Terry - covered in plaster dust and debris from the bombing - stepped forward, calmed the audience and in true theatrical tradition, the show went on!