In the show, pre-recorded on Tuesday, Will represented the UK with a performance of Doors' classic 'Light My Fire' (pictured left).
Whilst most were impressed, some were less interested. Canadian Idol's equivalent of Simon Cowell, record boss Zack Werner, told him: "The Bee Gees doing the Doors doesn't work for me. I hate it."
Polish judge Kuba Wojwodzski added: "You looked like Mr Bean singing Jim Morrison. If I was part of the Morrison family, I'd sue you."
Elias Rhabani, representative for the Arabic region, went as far as to claim that Will couldn't even sing. “Maybe you’ll become one of the most famous people in the world if you practise. Maybe you should have singing lessons.???
Simon Cowell fought Will's corner, however, telling him that he had made him "proud to be British."
It wasn't the only time that Cowell got annoyed by his fellow judges on the show. After Werner rubbished American Idol winner Kelly Clarkson, Cowell told him: "You're not fit to judge this girl."
But he didn't stop there. Cowell later went on to attack the whole show itself, saying: "You don't have to be a brain surgeon to realise this competition is ridiculous. The gulf between these singers is enormous - it's like comparing donkeys to racehorses. I honestly don't know why I'm here."
The performances will go out on networks around the world on Christmas Day. Each country will see a different version of the programme hosted by their own local presenter, although Ant and Dec did the job of fronting both the US and the UK version. The duo will also be back to exclusively host part two - the results show - on New Years' Day.