PREVIEW

The singer-songwriter and actress has revealed that she was an extra in the Australian rock band's music video for their 2000s song Stiff Upper Lip. During an appearance on Apple TV's A Carpool Karaoke Christmas, which was released on Sunday night, Gaga showed a clip of her late grandmother singing AC/DC's 1979 hit Highway to Hell before host Zane Lowe surprised her with an appearance by the band's lead singer Brian Johnson. "I brought you Brian Johnson for Christmas," Lowe quipped as the singer…”