The 24-year-old singer performed three songs. She began with 'Price Tag' before joining Tinie Temph and Taio Cruz for a rendition of the Bee Gees' 'You Should Be Dancing' and sang alongside Queen legends Brian May and Roger Taylor for 'We Will Rock You', reported Femalefirst online.
"I'm in shock right now. Tonight is a night to always remember and never forget. Blown away!! london2012," she tweeted.
"Oh what a night! So proud to represent the UK! Congratulations to everyone! Booooooom! (sic)," she added.