"Today my new co-host will be joining me on Live!, " Ripa anxiously told the audience on Monday's show, thanking fans and her guest co-hosts for helping out during her year of solo hosting.
"Kelly and I were friends, we've known about it for a long time," Seacrest said, adding that the pair had a hard time keeping the announcement a secret.
As RadarOnline.com previously reported, sources told CNN that Seacrest will host the show four days a week from New York and return to Los Angeles for the remainder of his time, the publication reports.
On Sunday, Ripa teased the big announcement, tweeting a video of herself sipping from a Live! with Kelly mug with a question mark drawn on it, saying, "Tune in tomorrow. Trust me!"
- Kelly Ripa Did NOT Ditch Robin Roberts' Wedding Over Feud With Former 'Live' Co-Host Michael Strahan: Source
- Memoir Wars: Kathie Lee Gifford 'Plans To Fight Back' At Kelly Ripa's Accusations About Regis Philbin In New Book
- Kelly Ripa & Mark Consuelos Under Fire With Fans Over 'Mundane' Revamped 'Live'
As RadarOnline.com readers know, Ripa claimed she was completely blindsided by show executives when Michael Strahan announced his plans to leave the show for GMA last summer without informing her first.
She's been hosting Live! solo for some time, with several co-host candidates appearing on the show, including Jerry O'Connell and Fred Savage.
Other repeat guest hosts have included Jimmy Kimmel, Bravo host Andy Cohen and Anderson Cooper.
As RadarOnline.com has reported, former NBC star Tamron Hall was urged to join Ripa as her Live! co-host. Sources said Hall ceremoniously left the Today show after being iced out by "more valuable" Megyn Kelly.
Are you excited to have Seacrest as Ripa's new co-host on Live!?
We pay for juicy info! Do you have a story for RadarOnline.com? Email us at firstname.lastname@example.org, or call us at (866) ON-RADAR (667-2327) any time, day or night.