Ryan Seacrest will also be back as the show's host, reported E! News.
"I am thrilled our consummate host, Mr Ryan Seacrest, is returning for Season 14, together with Jennifer, Harry and Keith," American Idol's creator and executive producer Simon Fuller said in a statement.
"Their interaction, warmth and experience made them an absolute joy to watch. I can't wait to see their evolution together continue next season," Fuller said.
"Jennifer, Keith, Harry and Ryan are the very best in the business at what they do, and I'm thrilled that they are returning to American Idol for another season.
The show is expected to undergo some changes. It will most likely be downsized to one episode per week when it returns in January.