"I had those Replacement shows come up the same time the (South American) tour came up, and it got to be a scheduling issue right out of the gate," Stinson tells Billboard. "I didn't want to f*** anyone up in Guns by saying, 'Hey, I can't do this tour' or anything like that. Luckily someone was able to reach out to Duff and he was amenable to the idea and was into doing it. It's Duff being the kind of good sport he is, trying to help Axl (Rose) out. So I'm like, 'Thanks dude, for covering my ass on this one.' I think people are gonna be really stoked about it. It's gonna be fun for everyone."

Rumors flew on Monday when Duff tweeted a photo of setlists full of GNR tunes, writing, "Argentina, Paraguay, Bolivia, Brazil! See y'all in the next few weeks, Si? GNR."

McKagan will fill-in for Stinson with the band beginning April 6 in Buenos Aires, Argentina, and continue for shows in Asuncion, Paraguay on April 9, La Paz, Bolivia on April 12, Recife, Brazil on April 15 and Fortaleza, Brazil on April 17.