Katy Perry Live At The Summertime Ball 2012 - Pictures The 'Firework' singer lit up the Wembley Stadium stage at the Summertime Ball 2012. See the best bits of Katy Perry's stunning set in pictures. 1. Katy Perry wore a polka dot two piece for her closing Summertime Ball 2012 set. 2. Katy Perry used a comic book themed set for her Summertime Ball performance. 3. Katy Perry won the award for the most colourful backing dancers at the Ball. 4. Katy Perry opened her set with hit single 'Hot N Cold'. 5. Katy Perry gave an energetic Summertime Ball 2012 performance. 6. Katy Perry was the final artist on the Wembley Stadium stage. 7. Katy Perry sang hits including 'Last Friday Night (T.G.I.F.)'. 8. Katy Perry also sang 'California Gurls' during her Summertime Ball 2012 performance. 9. Katy Perry also sang recent hit 'Part Of Me'. 10. Katy Perry on stage with backing dancers. 11. Katy Perry rocked the Wembley Stadium crowds during the Summertime Ball 2012. 12. Katy Perry's backing dancers wore bright yellow wigs. 13. Katy Perry belts out another massive hit. 14. Katy Perry's fans cheer on their idol. 15. Katy Perry lights up the stage during the final appearance of the night. 16. Katy Perry looks relaxed on stage in front of 80,000 fans. 17. Katy Perry puts the finishing touches to her set. 18. Katy Perry points to the heavens during the Summertime Ball 2012. 19. Katy Perry live at the Summertime Ball 2012. 20. Katy Perry live at the Summertime Ball 2012. Picture: Louise Roberts