According to CNN, the longtime TV personality and former American Idol host will be introduced by Ripa on Monday morning's broadcast.
Sources said 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!"
As Radar 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 Radar 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.
Now, she finally has her winner!
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