Last night saw the remaining five X Factor finalists perform live for the eighth time, singing two tracks each.
The acts sung both an Abba track and a Motown themed number, before the public were given their say.
This evening, Dermot O'Leary revealed that Union J and Rylan Clark had received the fewest public votes and would have to sing again.
It's the third time for both acts in the sing off, having been saved twice before each by the judges in the past.
In the sing off the pair will go head to head and the judges - Gary Barlow, Tulisa Contostavlos, Nicole Scherzinger and Louis Walsh - will decide which of the pair stays and goes.
Or, more likely, they'll cop out and send it to deadlock again.
Find out the X Factor results soon!
The X Factor 2012 continues next Saturday and Sunday on ITV1 and ITV1HD.