James Corden explains the origin of Carpool Karaoke

An hour before premiering the new Broadway edition of Carpool Karaoke on Monday night, James Corden appeared on CBS comrade Stephen Colbert’s show to explain the bit’s origin.

According to him, the whole thing started as a sketch for Britain’s Comic Relief charity, in which Corden picked up Wham!’s George Michael and drove around singing with him. Corden found the experience “joyful” and realized it could easily be transferred to the celebrity-filled carpool lanes of Los Angeles when he took over The Late Late Show. Unfortunately, Corden said that it took time for the idea to gain traction with artists.

“Imagine a recording artist. They said no,” Corden said. “There wasn’t anyone who would do it, and then there was a chance meeting with Mariah Carey, and she said, ‘OK, I’ll do it.'”

After Carey’s video, the bit slowly started gathering steam as it racked up famous guests one after another. These days, Carpool Karaoke is one of the most popular sketches in late-night TV, drawing in everyone from reclusive pop megastars like Adele to venerable Broadway legends like Audra McDonald and Jane Krakowski.

“We didn’t think it would turn out the way it has done, and it’s great,” Corden said.

Watch the full clip below.