While her predecessors Geri Halliwell and Natalie Imbruglia were unceremoniously booed to the rafters, Katy Perry made an altogether more successful impression as guest judge on The X Factor yesterday. Bubbly Katy bounded onstage to huge cheers from the Dublin audience, happily telling them, "Today we're going to give Simon a taste of his own poison!" She then gushed that co-judge Cheryl Cole (Tweedy, whatevs) looked "absolutely stunning". She clearly knows how to get on people's good sides. Katy said of her judging stint, "I'll understand the nerves involved and I'll "give people a fair shot, but if someone's bad, someone needs to tell them." We can't wait to watch her in action later this year. And look how tall she is next to teeny-tiny Cheryl!