The American Idol host is said to have paid $49 million (£30.6m) for the 2.87-acre property, reports TMZ.
The estate consists of a 9,200 square foot main house, three guest houses, and several cement ponds.
Seacrest allegedly paid very close to the asking price, with the deal set to be finalised later this week.
The television and radio presenter reportedly earns around $45 million per year, and is worth $125 million in total.
The house was previously owned by Will & Grace co-creator Max Mutchnick. DeGeneres paid $29 million for the estate, before buying the adjacent buildings.
DeGeneres and Seacrest worked together on American Idol for one season before the chatshow host left in 2010.
Ryan Seacrest appeared at last night's (May 14) Fox Upfront Presentation for 2012 in New York.