Everyone has become obsessed with James Corden's Carpool Karaoke, but what really happens behind-the-scenes while filming in the little car?
"It's SO hot in the car! No one knows this...I'll give you the whole scoop," he explained. "Basically, because they're recording sound, they can't have the A.C. on, and at that point in the year, which was like a month and a half ago, it's really hot in L.A. So for some reason I decided to wear this jacket with another thing on top of it, this whole thing, and I'm just sweating in the car, and Demi keeps looking back at me like, 'What's the matter with you?'"
He tried to brush it off, but he was a little worried the heat was going to mess up his memorization. "You want to make sure you know the words to Demi's song, she knows the words to my songs, and he knows the words. It's an interesting thing."