Things heat up when the arrival of Olly Murs causes a music mansion meltdown. The singers struggle to sing in Spanish when they take on a Liam Payne track. It all goes downhill for the mums when they are chased by a yeti down the UK's longest toboggan track. And one singer finally pulls ahead of the pack in the all-important seventh Sing-Off.

Things get emotional for one singer when the group take on a Spanish dance challenge. It all gets a bit cringeworthy when the mums take to the stage in a lip-sync battle. And in the final sing-off, one singer walks away with the elusive fast pass into the grand final.

It's the semi-final. The seven remaining singers are put to the test in a make-or-break performance at the world-famous Metropolis recording studio. All seven get to perform one track but only three can make it through to the grand final, and it's all down to the public vote. Who will win over the nation and earn their spot in the final and whose journey in the competition will end?