Paul Rodgers is currently on a tour celebrating the songs of his pre Bad Company band Free, on the "Free Spirit" tour. Led Zeppelin's Robert Plant, and AC/DC's Brian Johnson joined him for an encore Sunday Night of Barrett Strong's 1959 classic "Money (That's What I Want)."

For Plant and Rodgers, it's a reunion from decades ago when the two shared a manager in Peter Grant. Grant also signed Bad Company to Swan Song, used as a vehicle for the Zeppelin to promote its own products as well as acts who couldn't get another record deal with other major labels.

Johnson hasn't been fronting AC/DC for over a year, after hearing loss issues temporarily derailed the band's Rock Or Bust tour. Johnson said in an open letter to fans that he intends to solve his hearing problem and continue recording and touring, although he pointedly did not say whether he would be rejoining AC/DC

Here is fan filmed footage of the performance