Matt Cardle may haveDannii Minoguetold him to put his health before the XF, but the Essex boy battled on and performed renditions of Simon Cowell, warning that if he doesn't obey the music mogul, he could find himself in trouble.
The insider revealed: "Simon respects Matt as an artist and he doesn't want to stifle his creative side, but that certainly doesn't mean he is going to give him free rein to release whatever song he wants,"
"When it comes down to it, all Simon cares about is selling as many singles as possible and getting the Christmas No.1. If that means making Matt sing a cover, then that's what's going to happen... "
They added: "If he wants to truly be a success he will have to learn that Simon's the boss and what he says goes."