He's had Stevie Wonder in his passenger seat. He's shared a tea with Adele. He made Elton John don a wig! He's hosted Justin Bieber twice. Who could James Corden possibly get in his Range Rover next?!
From soaring to high notes that threaten to crack the windscreen to revealing her belief in alien life, all whilst wearing a cavernous wig (it makes Elton's look comparatively subtle), much like Sia herself, this is something a little bit different.