9. Katy Perry Vs. Lady Gaga: Greatest Hits!
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Katy Perry Vs. Lady Gaga: Their iTunes Festival Performances Compared
8. 9. Katy Perry Vs. Lady Gaga: Greatest Hits!
While everyone loves hearing new music from their pop idols... it's the fan favourite songs that bring you out in the first place! While Gaga performed her recent hit 'Applause' everything else on her setlist was completely brand new, but Katy made sure to bring along all her biggest hits like 'Teenage Dream' and 'I Kissed A Girl'!