Apparently, the mystery pop singer was Kavanagh (he was a pop singer, then resurfaced on the ITV Grease casting show, where he got to the final and then he auditioned for The Voice) and he's been tweeting about it.
I thought this week's ep was great! Interesting to see three shows featured. The Happy Days parts were bizarre, especially the 'mystery pop star' who refused to have his face shown on camera. His voice definitely sounded familiar, but I can't place it. Anthony Costa is a good shout, but I wondered about Lee Ryan (also from Blue)? One thing I'll say in his defence is that it was an odd audition, with Craig R-H effing and jeffing at him to 'get a performance'. It would have made more sense to just let him sing (as they did with Chico). That said, his voice did seem weak.
I thought the first episode was great. It did feel like they could easily have done a whole series (4 - 6 episodes) focussing on Charlie & The Chocolate Factory ("In the next episode...will the glass elevator finally get off the ground?" ). I enjoyed it, though and next week's ep does look fab.