Bryan celebrated the news on his Instagram Story, writing, "We're back!" Richie did the same, writing, "Excited to be back, y'all!"
"Season 20 here we come!" Seacrest wrote on his Instagram Story.
Rob Mills, executive vice president of Unscripted and Alternative Entertainment at Walt Disney Television, said the returning cast "are music and industry icons that have become synonymous with Idol on ABC."
"Their star power is unmatched, and their support is a gift to our contestants that have deeply benefited from their wisdom over the past four seasons -- and they’re ready to do it again," he continued. "As we begin a momentous season, I think it’s safe to say this dream team has officially cemented their legacy on Idol."
Of the show's upcoming milestone season, executive producer and showrunner Megan Wolflick said, "American Idol is still the original music show that genuinely creates superstars and continues to evolve to allow true artists to succeed in this unique business."
"The chemistry and passion Katy, Luke, Lionel and Ryan bring is second to none," she added. "We couldn’t be more ecstatic that they are returning for this iconic 20th season in search of the freshest new talent that this nation has to offer."
As for executive producer Eli Holzman, the CEO of Industrial Media, he said, "We are thrilled that Katy, Lionel, Luke and Ryan will be back to help discover our next American Idol."
"This dream team has selected and guided some of the most talented Idol contestants in the history of the series, and we can’t wait to see who they’ll find next," he expressed.
When it comes to who will be performing for the judges, Idol Across America, the virtual, nationwide auditions, will kick off Aug. 6 and run through Sept. 21. The virtual casting process began last season, and is how the eventual winner, Chayce Beckham, found his way to the show.
Hopefuls must be at least be 15 years old to audition, and are open to do so on any of the below dates, regardless of location.
Georgia, North Carolina, South Carolina (Aug. 6)
Connecticut, New Jersey, New York (Aug. 8)
Kansas, Nebraska, North Dakota, Oklahoma, South Dakota, Texas (Aug. 11)
Florida, Michigan, Virginia, West Virginia (Aug. 13)
Alabama, Arkansas, Louisiana, Mississippi (Aug. 16)
Indiana, Kentucky, Tennessee (Aug. 18)
Alaska, California, Hawaii, Nevada (Aug. 21)
Idaho, Montana, Oregon, Washington, Wyoming (Aug. 23)
Illinois, Iowa, Minnesota, Missouri, Wisconsin (Aug. 25)
Open Call: Nationwide (Aug. 27)
Arizona, Colorado, New Mexico, Utah (Aug. 31)
Maine, Massachusetts, New Hampshire, Rhode Island, Vermont (Sept. 2)
Delaware, Maryland, Ohio, Pennsylvania, Washington D.C. (Sept. 8)
Open Call: The South (Sept. 10)
Open Call: East Coast (Sept. 13)
Open Call: West Coast (Sept. 16)
Open Call: Nationwide (Sept. 21)
American Idol's fifth season on ABC and 20th overall will air in the spring of 2022.