The Pet Shop Boys unveiled their new soundtrack to the 1925 film Battleship Potemkin at a "unique" free concert in London's Trafalgar Square on Sunday.
The duo unveiled two new songs as part of the soundtrack
Thousands heard the pop duo perform the soundtrack with the Dresden Sinfoniker orchestra as the film was screened.
Singer Neil Tennant said: "We liked the idea that we were going to take something made in the 1920s and put contemporary electronic music to it."
People attending reported problems in reading the film's subtitles, however.
The 73-minute work included two new Pet Shop Boys songs.
The show was part of a season of events taking place in the square organised by Mayor Ken Livingstone and the Institute of Contemporary Arts (ICA).
"The ICA approached us because they knew we had a background of using film with our music - our first tour, for example, was directed by Derek Jarman," Tennant told BBC One's Breakfast on Friday.
Sergei Eisenstein's classic tells of a sailors' revolt in 1904, and has been a major influence on film-makers and artists.
Tennant said he was a fan of Soviet and Russian films after studying history at college.
"The director, Eisenstein, said that he wanted there to be a new soundtrack to the film every 10 years to keep it fresh," Tennant said.
He also said he and musical partner Chris Lowe had been keen to discover "whether we could write an hour and a quarter of continuous music".
Tennant said the new Pet Shop Boys' soundtrack "changes the way you see the movie", emphasising its "modernist quality".
"It's really exciting in London that you have got an event you can turn up and see the premiere of a new work," he said. "It's really a completely unique event."
Guardian newspaper reviewer Maddy Costa was not impressed, however, reporting that the screen was too low, preventing many in the audience from reading the film's subtitles.
"The Pet Shop Boys appeared so awed that the most they could provide was a portentous swirl of synthesised minor chords," she wrote. "At times the music felt positively inappropriate."
BBC Four is screening Battleship Potemkin on Saturday 18 September at 2240 BST, although it will not feature the Pet Shop Boys soundtrack.