Artwork: Crishna Simmons AKA Flickr user Kikishua.

Imogen Heap has made a new charity song for Great Ormond Street Hospital called "The Shepherdess" which sees Imogen experimenting with a totally un-rehearsed experimental piece of music at her live concert at Shepherds Bush Empire.

Immi improvised the mini-masterpiece where the key, tempo and time signature were chosen by the audience just a mere thirty seconds before she started to play and the end result is "The Shepherdess". All the proceeds from "The Shepherdess" will go to benefit Great Ormond Street hospital in London who operated and saved Immi's leg when she was just a wee tot of one year.

When asked about why she did the charity single, this is what she had to say:

"Because it's a local London Charity and because when I was one, they diagnosed me with Osteomyelitis. A brilliant surgeon then operated swiftly and saved my little leg. I've wanted to thank them ever since."

You can support Great Ormond Street hospital by purchasing the single here.