At the end of the first season final Keith Urban announced he would be leaving 'The Voice' as coach. He soon after was confirmed as the new judge on American Idol (2002). Speculation mounted in the media on who would replace him on The Voice Australia - candidates named included Darren Hayes, Vanessa Amorosi, Natalie Imbruglia, and John Farnham. Ricky Martin was officially named as Urban's replacement on 29 November 2012.
It's obvious the judges make their decision before the contestant starts performing.