The reality stars fend off stiff competition from rapper T.I., who climbs from 39 to two with his Rihanna collaboration 'Live Your Life'.
Beyoncé slips to three with 'If I Were A Boy', while The Killers score the highest new entry of the week, debuting at four with 'Human'.
Alesha Dixon also enjoys a successful week on the chart, climbing from eight to five with 'The Boy Does Nothing'.
Outside of the top ten, Duffy debuts at 22 with 'Rain On Your Parade', while Guns N' Roses land at 27 with long-awaited comeback single 'Chinese Democracy'.
The top ten singles in full (click to read our reviews):
1. (1) 'X Factor' Finalists 2008: 'Hero'
2. (39) T.I. ft. Rihanna: 'Live Your Life'
3. (2) Beyoncé: 'If I Were A Boy'
4. (-) The Killers: 'Human'
5. (8) Alesha Dixon: 'The Boy Does Nothing'
6. (3) Girls Aloud: 'The Promise'
7. (7) Katy Perry: 'Hot N Cold'
8. (4) Britney Spears: 'Womanizer'
9. (6) Guru Josh Project: 'Infinity 2008'
10. (5) Leona Lewis: 'Forgive Me'
Source: Official Chart Company
> Click here for this week's UK albums chart