Adam Levine v Christina Aguilera
These two judges on The Voice are constantly competing against each other, and famously had a rumoured blow-up behind the scenes on set earlier this year. Adam told his protoge candidate, Tony Lucca, to sing Jay Z's '99 Problems', as a subtle dig to Lucca's former Mickey Mouse club member and vicious judge, Christina. And when Christina found out, well, you can bet more than one voice was raised!
Photo by Getty Images Oct 26, 2012