Hetfield comments in the video, which was posted on Iggy Pop’s Facebook page:"Hey, Iggy. Happy 70th birthday. You don't look a day over 30. I've enjoyed immensely getting to know you over this year and have nothing but respect and love for you and what you've done for rebellious music. And I just wanna say that you're not only a survivor but a huge inspiration for me as I battle on into older age and enjoy every moment of it. So I think everyone there, in honor of Iggy and his 70th, should take their shirts off. Yeah! Have the faith! Keep the faith, brother! Take your shirt off."
Pop opened for Metallica at each of three shows Metallica played at the Foro Sol venue.
Metallica welcomed Pop on stage for the final encore, when Hetfield told the crowd, "METALLICA has much respect for the man coming out here to sing a song with us, and we're grateful that he's been able to be on this Mexico City tour with us. Please show your sign of respect and love to Mr. Iggy Pop."