Listen to Metallica on iHeartRadio

The guys in Metallica were pulling double duty at their Orion Music + More festival this weekend.  They surprised concertgoers Saturday by taking the stage under the name Dehaan to play their 1983 debut album "Kill 'Em All" in its entirety. 

Frontman James Hetfield hinted at the special 30th anniversary performance earlier that day with an Instagram photo of the stage and a caption about looking forward to seeing his "new favorite band" Deehan. Hetfield continued to tease the fans when he came out on stage by himself and asked if anyone knew anything about this unknown band from Baltimore.  But he was soon joined by the rest of Metallica, and the quartet kicked off a high-powered 55-minute show with the "Kill 'Em All" opener "Hit the Lights." 

Day One of the Detroit festival also featured the Red Hot Chili Peppers in the headlining slot, as well as performances from Rise Against, Dropkick Murphys, Silversun Pickups, and more.  Metallica returned to top the bill on Sunday after performances from Deftones, Gogol Bordello, Japandroids, and others. 

Photo Credit Getty Images