PETER Kay and Susan Boyle look set to rocket straight to the top of the charts with their spoof cover of the song I Know Him So Well.

The tune, recorded to raise money for Comic relief, is already at number one in the Amazon CD singles sales chart and the iTunes chart.

It could be a worldwide smash after fans petitioned Comic Relief organisers to release the song outside the UK.

The song was first made famous when it was performed by Elaine Paige and Barbara Dickson in the musical Chess.