The 42-year-old star confirmed on Thursday's episode of Live with Kelly & Ryan that he will host a reboot of the reality competition on ABC.
"It's going to be the best time," he said of the show. "It's going to be a lot of fun. We're auditioning soon."
Seacrest hosted American Idol throughout its original 15-season run on Fox from 2002 to April 2016.
"It's genuinely hard to put into words what American Idol means to me," Seacrest said in a statement. "I'm so grateful for the show and all the career and life opportunities it's allowed me to experience. It's been an incredible journey since day one.'
"To be asked to return this year, at my new home at Disney/ABC is an honor, if not a bit surreal," he confessed.
Seacrest will join new judge Katy Perry. The 32-year-old singer welcomed Seacrest back to the show in a tweet Thursday.
"I'm spicy, @RyanSeacrest is seasoned! All the right ingredients are coming together on @AmericanIdol. Have YOU auditioned? #TheNextIdol," she wrote.
ABC confirmed the revival in May following American Idol's final season on Fox. The network said the reboot will debut in 2018.