It is the third number one album for the operatic pop four-piece, whose members hail from France, Spain, Switzerland and the US.
Meanwhile, Stereophonics have to settle for a number two debut with their 'Best Of' compilation Decade In The Sun.
Last week's chart-topper, Out Of Control by Girls Aloud, slips to three, while Kings Of Leon bounce back to four with Only By The Night.
Other new entries in the top ten come from Enya, who bows at six with And Winter Came, and Christina Aguilera, whose hits compilation Keeps Gettin' Better lands at eight.
The top ten albums in full (click where possible for our reviews):
1. (-) Il Divo: 'The Promise'
2. (-) Stereophonics: 'Decade In The Sun - Best Of'
3. (1) Girls Aloud: 'Out of Control'
4. (6) Kings of Leon: 'Only By The Night'
5. (2) Pink: 'Funhouse'
6. (-) Enya: 'And Winter Came'
7. (3) Enrique Iglesias: 'Greatest Hits'
8. (7) Celine Dion: 'My Love - The Essential Collection'
9. (5) Snow Patrol: 'A Hundred Million Suns'
10. (-) Christina Aguilera: 'Keeps Gettin' Better - A Decade Of Hits'
Source: Official Chart Company
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