It’s beginning to look like The Replacements have a new member: Tonight in Atlanta, the band once again enlisted Green Day’s Billie Joe Armstrong, who first joined the band at the second weekend of Coachella last month, and now followed that up by appearing with the ‘Mats at the Shaky Knees Music Festival.

Coachella’s second weekend is under way now, and The Replacements took the stage tonight for the second of the reunited band’s appearances at the two-weekend fest — and dropped a big surprise on the crowd, as Green Day’ Billie Joe Armstrong joined the ‘Mats for part of the band’s set.