SiCo Brings Mr Nasty Back For Britain's Got Talent
Talent show hopefuls face a tough time as the auditions kick off in Cardiff...
In fact, Walliams' ribbing of his boss has already started. Before turning up for the auditions, he tweeted: "@SimonCowell I am going to wear the sparkly red dress for the BGT Cardiff auditions today. You always said I look beautiful in that."
You'll be pleased to hear he didn't keep his promise.