"Number 1" is a song composed by Tinchy Stryder featuring vocals from Dappy of N-Dubz, and co-written by Dappy, James Lavelle and Fraser T Smith, who is responsible for the production, from Tinchy Stryder's second studio album, Catch 22. The song was released as a single on 20 April 2009 from Tinchy Stryder's studio album Catch 22 and a remix was later included on N-Dubz's second studio album, Against All Odds.

The version released as a single and included on Catch 22 features verses by Dappy and Stryder only; however, the version that appears on Against All Odds features new verses by Tulisa Contostavlos and Fazer. "Number 1" topped the UK Singles Chart, a position it maintained for three weeks. Internationally, the song also topped the charts in the Republic of Ireland as well as peaking within the top forty of the charts in Denmark. It is notably the first - and so far only - song in music history entitled "Number 1" to actually peak at number one on any national singles chart in the world.

According to producers James Lavelle and Fraser T Smith in an interview with HitQuarters, although Dappy was involved in the writing of the song, he had worked with an up-and coming artist J-Rhymz and whilst in the studio with the young singer/songwriter, his appearance on the final version happened by accident.

"We’d worked with him on a track called "Strong Again" ... and we wanted to work with him more because he’s an amazing talent. So 'Number 1' came about from a co-writing session. Dappy put the hook down and it sounded so good we thought it had to stay."

"Number 1" has received positive reviews from Digital Spy and the BBC. David Balls of Digital Spy gave the song a positive review: "A savvy collaboration with urban pop trio N-Dubz, this offering places Tinchy's distinctively gritty vocals over shimmering disco beats and even throws in a few strings for good measure. The result, while catchy enough, falls a little short of its predecessor and will no doubt leave some grime enthusiasts claiming: "I don't understand how you're number one".BBC chart blog also gave the song a positive review: "N-Dubz. Everything they do raises a grin to my chops. Dappy's insistence on throwing in a "nah-nah-naiii-hee" as soon as his microphone is switched on is a brilliant pop thing. Tinchy's singy-raps, contrasting nicely with Dappy's rappy-singing. And I use the word 'contrasting' quite wrongly there. The song was awarded a 4 star rating.

...
Wikipedia