The album has been conceived as a mix of a classic songs and re-recorded cover versions performed by newer artists. The acts involved include Paul McCartney, Duffy, Brian Wilson, Rufus Wainwright and Hot Chip.
A War Child spokesperson said: "We have been overwhelmed and amazed by the response to the project. The wealth of talent who have contacted us wishing to support the charity and contribute to the album is humbling and we are delighted to have been able to change our deadlines to accommodate some of them. It was impossible to say no."