P&O's Workplace Choir have been constantly rehearsing for their performance with Susan Boyle, set to take place tonight at the Hammersmith Apollo, London.

Taking to Twitter, the group have been posting pictures and even liaising with the star, who was the runner up in ITV's Britain's Got Talent in 2009.

Conductor, Hillary Campbell has also taken to Twitter over the choir's progress.

The choir even tweeted a picture of an empty Hammersmith Apollo theatre, which is anticipated to be a full house tomorrow.

When the news first broke, spokesman for P&O, Brian Rees, said: "We were pleasantly surprised with the warm reception and packed house at our last performance, which was in Dover Town Hall a month ago. "

He added: "Next thing we knew, Susan Boyle’s agent was on the line asking if we can perform at The Apollo.

"It’s a once in a lifetime opportunity that caught us completely off guard.

"It is both extremely flattering for our choristers, and a little nerve-racking as it means getting to grips with a whole new set of material.

"When you bear in mind that our choir didn’t even exist ten months ago, to be treading the boards with an internationally acclaimed star so soon really is the stuff that dreams are made of."