Johnson and Gaga then launch into the duet “Highway to Hell,” with Gaga and Johnson duetting their raw, complementary vocals on the 1979 rock classic. At one point, Gaga and Johnson hold hands as Gaga helps re-steer the steering wheel.

“I got it! I’m using my secret weapon,” Johnson laughs as Gaga replies, “We’re all going to die!”

Then Gaga Johnson makes a revelation. “Do you want to hear something funny? “I was in the ‘Stiff Upper Lip’ video,” says Gaga Johnson.

“No, it wasn’t you!” Johnson replies.

“I was 17 and I was an extra at the back. I was headbanging and they were like, ‘Hmmm.’ No headbanging, we want it to be modern,” Gaga said. “And I thought, ‘No, there’s only one step I can take.'”

In an earlier part of the episode, Gaga shows a video of her grandmother screaming and cackling as she sings the lyrics to “Highway to Hell.” “She had a really hard life and was definitely the most positive person,” Gaga Lowe explains.

The special, A Carpool Karaoke ChristmasThe film also stars Dua Lipa and Chappell Roan, who brings her parents along for the trip to Missouri.

“What she stands for is a lot of hope, but what she taught me as a father is respect for other people and all people,” Roan’s father says in part of the episode. “I want people to understand this: Everything about her is about loving everyone, and that’s what she taught me.”