Ten of thousands of people went wild as Jessie J joined Will.i.am on stage to perform We all know how to party in the UK!
Jessie J wore a blue and black sheer embellished with bright gold and orange piping, a high slit and feather detailing from the waist below by world renowned Falguni and Shane Peacock.
The dress is from their Spring Summer'12 collection which they showcased at the Mercedes Benz Fashion Week in New York last year.
Everyone lined in front of The Mall to watch the show as fireworks and lights lit up the queen's iconic residence in central London. Paul McCartney, Elton John and Cliff Richard also paid tribute to the queen alongside younger British artists, in a programme representing all the decades of her 60-year reign.