Louis Walsh has poked fun at Simon Cowell for wearing stacked heels.
The Irish judge was whisked to the US at the last minute to stand in for his X Factor boss at the Kansas leg of the US X Factor auditions, after Simon fell ill with bronchitis.
Louis joked: "I'm stepping into Simon's shoes... but my shoes are flat," The Sun reported.
Fellow judge LA Reid also had a pop at Simon, with the music producer saying: "The good news is we're having a great time. The bad news is that we're having a great time."
Louis has formed an unlikely friendship with judge Britney Spears, saying of the Toxic singer: "Britney and I are bonding," while the US singer tweeted: "We'll miss you Louis! See you soon."
Meanwhile Reid said of his relationship with Britney: "We get along good..." before looking at Louis and joking: "Him, not so much."