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15 Hot Fall Albums

''I never made a record before where I stayed up until 4 a.m.!'' Simpson says of working with producers Timbaland and the Neptunes' Chad Hugo on her new as-yet-untitled disc. ''I was running back and forth between Chad in one studio and Tim's camp in another!'' A big Gym Class Heroes fan, the pop star also enlisted Travis McCoy, who raps on the track ''Murder.'' More help came courtesy of acclaimed Ethiopian songwriter Kenna. ''I went to people who were more about discovering my life at a new time,'' Simpson says. ''I just felt like having fun, shaking my booty and having a party [vibe] in the studio.''