James Corden's wife got a call from this A-lister while in the bathroom

James Corden isn't sure when his popular "Carpool Karaoke" segment will return to The Late Late Show—"I hope so much that we'll be able to do it before the end of the year"—so he spent his time with The Ellen DeGeneres Show reminiscing on his 2015 installment with Stevie Wonder.

"Stevie Wonder was, I think, a real turning point for that segment on our show because it was incredibly moving," Corden said. "We came up with the idea—and I didn't tell my wife—we thought maybe that it'll be fun if Stevie would call Julia, my wife, and sing 'I Just Called to Say James Loves You."

The original Grammy-nominated 1984 Wonder song, of course, is titled "I Just Called To Say I Love You."

Anyway, back to Corden:

"I didn't tell her that he was gonna call, and he did, and what's on TV is really moving. I couldn't help but be overwhelmed by it. ... What I didn't know is when I got home, my wife Julia was actually in a bathroom stall at a restaurant when the phone rang. So, I had this gorgeous image of her just being completely overwhelmed with emotion, but she was just literally in a toilet at a restaurant."

Watch Corden's full interview below.