Related Katy Perry is back with a ‘Roar’ — hear her new single now Come fall, though, Americas divas will step in with higher-proof stuff. Katy Perry and Lady Gaga have already poured the first two shots: After announcing release dates for their respective albums, Prism and ARTPOP, the two unleashed massive first singles within the same 24 hours. Both women vow that theyve reinvented themselvesPerrys determined to stay dominant following a record-breaking string of No. 1s, and Gaga is fighting back from a major case of over-the-top-itis. (So far, this mostly seems to mean theyre both wearing fewer wigs.) First, Perry delivered Roar, an earnest empowerment anthem with an organic feel and some well-placed winks. Then Gaga rushed out Applause, a relatively streamlined, club-ready rumination on fame. Miley Cyrus, meanwhile, has been reveling in her fame rather than puzzling over it. Right now shes musics primo provocateur, the wild child outgunning all the older stars. ( Read about how she triumphed at the VMAs. ) The onetime Hannah Montana has genuinely remade herself, deep-sixing her Disney past so she can twerk with rap stars and conjure up a smash like We Cant Stop. Her delightfully named Bangerz should make a fascinating comparison with the album expected from fellow Disney seedling Britney Spears, whom Cyrus recently called the one person in my life who gets her kind of fame. That Spears has graduated to pop godmother at 31 shows just how fast the years flip by on the diva calendar. If Rihanna seems unchanged, its because she hasnt taken a breather since her 2005 debut, turning out hit-packed albums every year. Shes one of three powerhouses with still-unconfirmed albums that, diva willing, well see later this season: Beyonces people have denied rumors that she threw out 50 tracks intended for her long-anticipated fifth effort, and Mariah Carey delayed The Art of Letting Go after releasing the underwhelming Triumphant (Get Em) and the much better #Beautiful. Carey in particular cant be heartened by the success of Ariana Grande, a big-voiced Nickelodeon talent with a 90s-R&B fixation: This summer Grande broke into the top 10 with the very Mimi-esque The Way, and her debut, Yours Truly, is due in September. Need some Y-chromosome counter-programming?