Andrew Muir's song on Britain's got talent

[Le Chat]

Andrew Muir, the Scottish guy sang (badly) "Imagine." After the performance, when criticised by the judges for his song choice, he said " I didn't choose it" or "I didn't want to do that one." Or words to that effect.
So does that mean that he's not an independent singer and not in charge of his own song choice? After all all the other artistes did their 'own' routines. Anyone know why he couldn't choose his own song?

[Le Chat]

Sorry folks! Just seen this question asked in media and tv section.