The 24-year-old, real name Costadinos Contostavlos, bumped last Sunday's champions One Direction and 'What Makes You Beautiful' down to third place behind Maroon 5, who finish as runners-up for a fourth week with their Christina Aguilera collaboration 'Moves Like Jagger'.
Dappy first topped the chart in 2009 as a featured artist on Tinchy Stryder's 'Number One' and has collected seven top 20 hits as part of N-Dubz.
Elsewhere, a double bill of new entries in the shape of Jason Derulo's 'It Girl' and 'I Wont Let You Go' by James Morrison completes the top five, while Pixie Lott trips three to six with 'All About Tonight'.
Former album chart victor Ed Sheeran soars to seven from 14 with 'The A Team', Olly Murs drops down four to eight with 'Heart Skips A Beat' and Damien Rice's 2002 track 'Cannonball' makes a shock return to the Top 10 at nine. The song has soared an enormous 30 places after it was covered on The X Factor by contestant John Adams.
The big shifts continue into the double digits, as Bad Meets Evil jump nine to 13 with 'Lighters', Example collapses from six to 14 with 'Stay Awake', and 'All Fired Up' by The Saturdays tumbles ten to 15.
The most significant change in the best-sellers, however, belongs to David Guetta's Usher team-up 'Without You', which climbs a massive 12 places to 19.
The DJ now finds himself wedged between Leona Lewis and Avicii's 'Collide' and 'You Need Me, I Don't Need You' by Ed Sheeran, down eight places apiece to 18 and 20.
The Top 10 in full:
1. (-) Dappy: 'No Regrets'
2. (2) Maroon 5 ft. Christina Aguilera: 'Moves Like Jagger'
3. (1) One Direction: 'What Makes You Beautiful'
4. (-) Jason Derulo: 'It Girl'
5. (-) James Morrison: 'I Won't Let You Go'
6. (3) Pixie Lott: 'All About Tonight'
7. (14) Ed Sheeran: 'The A Team'
8. (4) Olly Murs ft. Rizzle Kicks: 'Heart Skips A Beat'
9. (39) Damien Rice: 'Cannonball'
10. (9) Will Young: 'Jealousy'
Source: Official Charts Company
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