Katy Perry has compared X Factor judges Simon Cowell and Louis Walsh to a ‘sweet old couple.’

The California Girls singer stood in for Dannii Minogue at the Dublin auditions for the show and said that Louis purposely puts through rubbish acts to annoy his boss. She added:

“People see them bitching, but deep down they are very much in love.”

Katy was seen ogling a lifeguard on Saturday night’s X Factor and received a great reaction from viewers, who loved her quirky judging style.