Simon Cowell is back with a vengeance on the X Factor USA judging panel, tweeting banter at co-judges, following his absence due to a bout of bronchitis.

Louis Walsh kept the TV mogul’s seat warm for the Kansas auditions of the American version of the singing competition, where he bonded with fellow judges Britney Spears, Demi Lovato and LA Reid while Simon was bed-bound.

Simon – who returned for the San Francisco auditions – proved that his sharp tongue had not disappeared when he tweeted: “Unfortunately Britney & Demi are now known as the gruesome twosome. V happy to be back – Demi more annoying than ever, Britney has grown claws!”

Britney replied: “And I’m not afraid to use them!”

The Toxic singer had earlier joked that they were planning to be tough on Simon and confirmed this by saying, “Simon better, it’s adorable! I’m glad @SimonCowell is feeling better. I know @ddlovato, @LA_Reid & I aren’t cutting him any slack today!”

But Britney showed her true place in the hierarchy when she added: “Yay! Simon approves of my pink hair!”