CBS / YouTube

Sia Teaches James Corden How To Sing Like Sia On Carpool Karaoke

She also revealed why she hides her face — and why she believes in aliens.

James Corden has been riding with an all-star entourage lately.

After inviting Justin Bieber and Adele to his morning commute, The Late Late Show host has found a new carpool partner in Sia -- wearing her signature face-covering wig, of course.

Corden picked up Sia from the sidewalk, where she was wandering blindly under one of her wigs. She never showed her face to the camera, but she did happily break into several of her own hits, including “Chandelier,” “Elastic Heart,” and Rihanna’s “Diamonds."

Sia also took the time to explain why she’s so careful about covering her face up these days. "I don’t wear this unless there’s cameras around,” she said. "I only wear this to try and maintain a modicum of privacy."

She continued to disclose how her history of substance abuse informed her decision to bring a little mystery into her public persona. “I was an alcoholic and a drug addict, and I sobered up and decided I didn’t want to be an artist anymore because I was starting to get a little bit famous, and it was destabilizing in some way,” she told Corden. "So I thought, what doesn’t exist in pop music at the moment? And it was mystery. There’s pictures on Instagram of everyone at the dentist."

Sia’s holding on tight to her enigma, but she’s happy to share it with others: She gave Corden his own bicolor wig and taught him how to sing her songs exactly like she sings them (well, almost).

Watch Corden get his very own singing lesson below.