Metallica paid tribute to Green Day's Billie Joe Armstrong during their headline performance at New Orleans' Voodoo Festival.

They stepped in to replace Green Day, who pulled out of the New Orleans festival so that Billie Joe Armstrong could focus on his rehab treatment, and gave their support to the singer by briefly playing "American Idiot".

According to MTV, after two songs into their headline set, Metallica front man Hetfield joked: "We are Green Day…except a little taller." The website also states that the singer dedicated 'Battery' to the trouble Green Day front man, saying: "This one's for Billie." Check it out: