Walsh's new locks are the source of much speculation among his fellow judges, who doubt his claims that it is totally natural and his own.
[Louis Walsh's new locks - left. Louis Walsh's old locks - right]
"The Louis Walsh hairdo - everyone's intrigued," comments Barlow.
Contostavlos adds: "He's had some miraculous growth spurt."
Walsh remains defiant about his new style, claiming it is "just me". "I've got a very good hairdresser," he tells the cameras.
A perplexed Barlow says: "I don't know what he's had done, and to be honest, I'm not going to even ask."
When Walsh claims that it's the "lighting" that makes his hair look different, Barlow jokes: "Highly unlikely... He's looking good for 78."
The Irish music mogul refuses to back down, arguing that his co-stars are just jealous of his youthful looks.
"They can't understand why I'm not ageing but I look after myself," he says.
At the X Factor series nine launch, Walsh told Digital Spy that his youthful looks were down to techniques that "Simon Cowell taught [him]".
The Xtra Factor airs on Saturday, September 1 at 9.25pm on ITV2.