Watch Amanda Holden and Sheridan Smith sing "I Know Him So Well" from Chess

Holden said today: "I got a great friendship out of this song in Sheridan Smith. I'd loved her for years and we've always hugged when we met but we didn't know each other. I really wanted her to duet with me on "I Know Him So Well" so I asked David Walliams for her number. She was heavily pregnant but she couldn't have been nicer or more enthusiastic when I called her and the final result is better than I even imagined."

The number is part of Holden's new album of musical tunes, which is set to be released on 2 October.

You can listen to the song below: