The new Hollywood Vampires album is almost certainly the most star-studded rock record of the year — but Johnny Depp, who worked alongside Alice Cooper on the project, says it really didn't start out that way.

"I had already written a bunch of music, and we started recording and then it became this Vampire thing," Depp recalled during a visit to Jimmy Kimmel Live! last night. Looking back on the sessions -- which ended up luring the likes of Paul McCartney, Joe Walsh and Joe Perry -- he laughed, "It was pretty shocking."

The record, which evolved over a period of several years, was inspired by Cooper's years spent partying with an Los Angeles-based crew of liquor-loving rock stars that included Keith Moon, John Lennon, Ringo Starr and Harry Nilsson. The final track listing includes a new song, the Depp co-write "Dead Drunk Friends," that sums up the album's tongue-in-cheek spirit; as Cooper put it earlier this year, "All those guys would have totally got it. They had the same sense of humor. If you told them you were going to do an album after they were gone called ‘All My Dead Drunk Friends,’ they would have died laughing."

The process proved instructive in more ways than one for Depp, who told Kimmel he used Perry while preparing for his role as infamous Boston gangster Whitey Bulger in his latest film, Black Mass. "Joe's got a pretty thick Boston accent," he pointed out. "So I just sponged it."

It seems unlikely that the entire Hollywood Vampires gang will find its way back onstage for any single live date, but fans will have a few opportunities to find out starting next week, when Cooper, Depp and Perry lead a band that's currently scheduled to include Guns N' Roses vets Duff McKagan and Matt Sorum through a pair of gigs at the Roxy on L.A.'s Sunset Strip Sept. 16 and 17.

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