Katy wowed viewers last night (20 October) after dressing up as a tiger and singing her recent No1 single 'Roar'.
Musician John, meanwhile, was also on the stage at London's O2 Arena performing to hundreds of his own fans.
Once their shows were over, Katy joined her beau John and together they headed to the exclusive Shoreditch House in east London.
The pair were thought to have partied until a very impressive 4.30am before leaving separately...and then meeting up in the same car!
Katy and John have always remained fairly tight-lipped about exactly what is going on between them, but we think it's safe to say they are very much more on than off at the moment.
One thing is for sure, Katy looked extremely happy to be in his company!
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