INGLEWOOD, Calif. — Jennifer Lopez and Steven Tyler will join Randy Jackson as “American Idol” judges next season, after months of turnover and speculation about the future of TV’s top-rated show.

Fox finally assembled the new pieces of the “Idol” panel that will be returned to its original three-member format for Season 10.

Actress-singer-dancer Lopez and Aerosmith frontman Tyler will have the job of trying to match the offbeat chemistry of former judges Simon Cowell and Paula Abdul.

Cowell announced last January that he planned to leave to launch a new talent show for Fox in 2011, with newcomers Ellen DeGeneres and Kara DioGuardi exiting this summer. Abdul left in 2009 over a contract dispute.

Lopez and Tyler could help “American Idol” reinvent itself for the new season, when it will try to stem a ratings slide and bring in younger viewers. The show’s audience has been gradually aging, and advertisers prefer to pitch to young adults.