Ah, to bang one’s head again

WHAT’S Flea’s favorite Metallica song? That would be the vintage shred-a-thon “Fight Fire With Fire,” a fact revealed near the end of Metallica’s show at the Wiltern on Wednesday. That’s when the Red Hot Chili Peppers bassist, who organized the concert as the annual fundraiser for his Silverlake Conservatory of Music, stepped from the wings and played bass on a scorching rendition of the 1984 song.

Flea’s guest spot capped an impressive return to action for the headbanging headliner, which has been all but absent for four years. “We haven’t played here in a long time,” singer James Hetfield said at Metallica’s first show in L.A. since 2004. “It feels good to be playing live again.”

With their first studio album since 2003’s “St. Anger” set to come out in September, the hard-rock titans, who also play Saturday at the KROQ Weenie Roast at Verizon Wireless Amphitheater in Irvine, figure to be back full force.

 richard.cromelin@latimes.com