I did wonder though about James. He was chewing gum it seemed.
I noticed the gum chewing as well in one of the video clips and my first reaction was,
wtf, how can he sing while chewing gum?! But I think it may actually have a purpose - possibly to keep tension out of his jaw and tongue base muscles. That kind of tension raises the larynx which I think has been his biggest issue in recent years, along with bringing up too much 'weight' from chest voice/heavy mechanism. The gum chewing is likely a strategy against these tensions, which by releasing the tension allows for the relaxed jaw and open throat needed for beautiful, unhindered high notes
That's my unofficial/unconfirmed theory!
I say whatever works for him is great! As long as he doesn't accidentally spit it on someone in the front row!