It's not very often you go to a concert and candyfloss is being sold alongside the Smirnoff Ice and lager. But then not everyone has the kid in a candystore mindset of Katy Perry.

Hammersmith Apollo is transformed into a dreamworld of candy canes, fluffy pink clouds and fairground kitsch for the arrival of Katy tonight, playing her second live date in the capital. It's a curious sight as pre-teen girls squeal in delight at the innocent delights their favourite popstar brings shortly before singing along to songs like 'Ur So Gay' and 'I Kissed A Girl'.Lets not get too broadsheet about this though. What Katy Perry does better than anyone in pop is fun. There is no S&M flirtation or allusions to high art, what you see is what you get with Perry and what we see tonight includes dancing gingerbread men, giant purple catsand a laser show that rivals the Super Moon for the best thing we've seen in the sky recently.

Katy bounds out onto the stage and delivers a two hour long, hit packed set with 'Teenage Dream' impressing early on. Perry herself would probably admit that she is not the best singer and certainly not the best dancer in the world but what she does so well is make everyone feel like they're partying with their best friend. She invites a group of fans onstage, throws chocolate out into the crowd and even gets one man to throw his t-shirt at her. Sniffing it, Katy jokes that "he is naked now."

Naked is one thing Katy never is, with a myriad of costume changes throughout the evening. This culminates in a quick change masterpiece during 'Hot 'n' Cold' that sees Katy wearing more outfits that most people get through in a lifetime.

In between costume changes, dancing cats, candyfloss and a story of how Katy is in love with a mystery bakers boy come some of the best pop songs of the past century. It's easy to forget that Katy P has only got two albums such is the size of her hits catalogue. 'I Kissed A Girl' starts in a jazz lounge style before bursting into life as the kick ass anthem we all know whilst 'E.T.' sees the aformentioned laser show feel like alien abduction might be about to happen imminently.

It is 'Firework' that reigns supreme though. Despite being the third single from Katy's second album, it feels like her defining moment. The roof positively lifts off as thousand of people, all of whom are clearly feeling like a plastic bag, bellow the words back at the blue wigged ring master of fun stood centre stage. It's a magical moment from what is a unforgettably fun night.