The band have announced that the track will be the final single released from their hit album Progress.
They were inspired to write the ballad after watching a private screening of the movie in LA with the film's director Paul W.S. Anderson.
Speaking about the single, band member Gary Barlow said: 'The film is visually so rich and beautiful that our main challenge was to then match it musically.
'We've returned to guitars, real pianos and a conventional song structure to achieve this. We also thought that the Musketeers reminded us of ourselves.'
The single will be released on August 22 but it is available now for digital download through Polydor Records.