"Number 1" is a song by British rapper Tinchy Stryder featuring vocals from Dappy of N-Dubz and co-written by Dappy, James Lavelle and Fraser T. Smith, who produced the track, for Stryder's second studio album, Catch 22.

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.

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".

Dappy's insistence on throwing in a "nah-nah-naiii-hee" as soon as his microphone is switched on is a brilliant pop thing.

[5] "Number 1" entered at the top of the UK Singles Chart on 26 April 2009 – for the week ending dated 2 May 2009 – selling 87,000 copies in its first week[6] and beating competition from La Roux's "In for the Kill" with over 20,000 copies, according to the All Around the World website.

The video frequently cuts between scenes with both N-Dubz and Stryder, two provocative female dancers and a string quartet.