Now that Metallica and Lou Reed have given the public the full Monty on their double-disc collaboration ‘Lulu’ by streaming the entire album on their website, the music icons are talking about their brave, ambitious, Frankenstein.

In an interview with the UK newspaper The Guardian, Metallica drummer Lars Ulrich, Reed and producer Hal Wilner talked about the history of ‘Lulu,’ the creative unity between the seemingly disparate artists and the musical sessions that yielded the fascinating album

“This has so much rage, it's thrilling," Reed said. “I've waited for a long time to have a shot at doing something like this with the right people. I'm energized and jacked up. Sometimes I find it so emotional I have to get up and turn it off.”

The seeds of ‘Lulu’ were planted after Metallica played the Velvet Underground songs ‘Sweet Jane’ and ‘White Light/White Heat’ at New York’s Madison Square Garden in October 2009 at the Rock and Roll Hall of Fame’s 25th anniversary concert. Reed proposed that the two legends should collaborate on a project. Two years later, ‘Lulu’ was conceived over a 10-day period at Metallica’s studio in San Rafael, Calif.

Originally, ‘Lulu’ was supposed to be an album of obscure Lou Reeed covers, but 10 days before Wilner and Reed arrived at Metallica’s compound, Reed decided that the album should be a spontaneous creation to accompany an avant-garde play directed by Robert Wilson with music by Reed. ‘Lulu’ combines elements from two morality plays written by Frank Wedekind at the turn of the 20th Century, Erdgeist (Earth Spirit) and Die Büchse der Pandora (Pandora's Box), though the music Metallica and Reed came up with for the project is entirely original.

“I didn't expect to be involved in a process of this magnitude,” Ulrich told The Guardian. "I didn't know we were going to be so involved on a creative level. I was perfectly happy in a perverse way to be a backing band, because that's something we've never done. I'm invigorated at how absolutely awesome the record turned out.”

Since Reed wrote the lyrics before working on the music with Metallica, they were able to focus intently on the music during the 10 days they spent together. “It offered us an incredible opportunity to do something that had no boundaries around it," Ulrich says. "We could concentrate on playing.”