The Hackney-born singer took to the Festival Republic stage in a yellow and orange dress and performed seven tracks from her critically acclaimed LP.
After opening with her latest single 'Yellow', she performed 'Hold on to Your Misery', 'One Eye Closed' and 'Hoarder'.
The star - real name Anita Blay - then dedicated the song 'Mexico' to her friend in the audience, adding: "Told you I would get here!"
She closed her 40 minute set with 'Asthma Attack' and 'I Deserve It' before thanking the lively crowd.
Digital Spy is bringing you news from Reading Festival 2011 all weekend. Click here to read our full coverage of the music event.
Watch CocknBullkid perform a rendition of Plan B's 'She Said' with Clare Maguire below: