Def Leppard is "about 85, 90 percent finished" with its next album, which frontman Joe Elliott describes as "a very rock album" tentatively titled "Songs From the Sparkle Lounge."

"I'm not gonna say it's radically different to anything we've ever done," Elliott tells Billboard.com. "There's classic Def Leppard. There's stuff that sounds like it's going back to the middle, late-'70s AC/DC and new wave-type sounding stuff. There's definitely some moments on it where anybody that's familiar with our music will go, 'Whoa! I wasn't expecting that!' We've just been very adventurous, musically, on certain numbers."

Elliott says the "Sparkle Lounge" album title refers to a room the group maintained backstage during its 2006 tour dates, where the musicians would congregate with co-producer and live sound technician Ronan McHugh to work up and record ideas.

"It was a mini (drum) kit, mini amps, a tape recorder and sparkly lights," Elliott recalls. "It had to be on call, like a doctor, so if somebody went, 'I've got this idea, you just run it, plug up, turn on and bang it out, and then you could work on it over the next few days. We've never, ever written on the road before, so this definitely came from a different head space."

Elliott says Def Leppard has finished 11 songs during month-long stints in January and April in Dublin. He expects the group to work on at least two more songs before settling on a final track list and release date. It will be Def Leppard's first set of new material since 2002's "X" and follows the 2006 covers collection "Yeah!"

But Elliott says the group won't be previewing any of the new songs on the road this summer, where it's touring mostly with Styx and Foreigner. "Nowadays, you play one song and it's gonna be on YouTube two minutes later and everyone will know it six months before the thing comes out," Elliott says. "That's just a sad indictment of the way things are."