Remodeled during Seacrest's ownership, the 1974 Mediterranean belonged to Oscar-winning actor Richard Dreyfuss before Costner purchased it in 1995 for $2.7 million.
The 10,000-square-foot villa, which sits on nearly an acre of hilltop with canyon and city views, features a gym, a wine cellar and a screening room, as well as a tennis court and a swimming pool. Including the guesthouse, the property has six bedrooms and 61/2 bathrooms.
Seacrest, 37, has hosted "American Idol" since 2002. He was a "Today" special correspondent during the 2012 London Olympics.
It was recently announced that Seacrest is leaving his spot as "E! News" co-host. His producing credits include "Shahs of Sunset" (2012), "Food Revolution" (2010) and "Keeping Up With the Kardashians" (2007-10).
Seacrest first put the house on the market in 2010 at $14.95 million. He bought TV host Ellen DeGeneres' compound in Beverly Hills for $37.5 million this year.
Kurt Rappaport of Westside Estate Agency, Beverly Hills, was Seacrest's listing agent. Linda May of Coldwell Banker's Beverly Hills North office represented the buyer.
Not quite a killing for 'Dexter'
He didn't exactly make a killing, but "Dexter" star Michael C. Hall has parted ways with his house in the Hollywood Hills for $1,937,500. The actor bought the property in 2008 for $1.75 million, public records show.
Once a 1933 Spanish-style home with a red tile roof, the house was modernized by mid-century architect Hal Levitt, who used it as his personal residence for four decades starting in 1964.
Large windows and a sliding glass door bring light into the vaulted-ceiling living room. The redesigned kitchen, which features Italian tile floors, opens to a patio with a fire pit. The backyard pool is described in the listing as "sleek and dexterous."
The 3,525-square-foot house features a gym, four bedrooms and five bathrooms. There are canyon views.
Hall, 41, has starred in the title role on "Dexter" since 2006 and was on HBO's "Six Feet Under" (2001-05). He will be in "Kill Your Darlings," a film set for release next year.
Jeff Kohl and Josh Myler of the Agency were the listing agents. Dustin Cumming of Hilton & Hyland represented the buyer.
One fewer distraction for new co-host?
Daytime talk-show co-host and Fox football analyst Michael Strahan and his fiancee, former model Nicole Murphy, have put a town house in Hermosa Beach up for sale at $1.849 million.
Set on a walk street within a block of the beach, the 2,560-square-foot custom house features two living rooms, an elevator, a rooftop deck, two master bedroom suites, another bedroom and four bathrooms.
Strahan, 40, is the new co-host with Kelly Ripa on "Live! With Kelly and Michael." He replaces longtime co-host Regis Philbin, who retired in November. The defensive end played for the New York Giants his entire NFL career, setting a record for sacks in a single season and retiring in 2008 after winning Super Bowl XLII. He starred in the 2009 TV series "Brothers."
Murphy, 44, was married to comedian Eddie Murphy from 1993 to 2006. She stars in the reality series "Hollywood Exes," which documents five high-profile women who are former wives of Hollywood A-listers or music icons.