Is there an emptiness in your life that only more Backstreet Boys music can fill? Great news! The Backstreet Boys are working on their sixth album. The now-quartet recently hit up the studio while touring Europe, and plan to work on some more new material when their U.S. tour wraps in early September. Backstreeter Howie Dorough even says the group might work with pop producer extraordinaire Max Martin, who teamed with the Boys on their hits "I Want It That Way" and "Show Me the Meaning of Being Lonely." But wait, there's more: Both Dorough and A.J. McLean are nearly finished working on their respective solo albums. Release dates for those solo discs have not been announced yet.