Melissa Gilbert, 48, is engaged to former "The West Wing" star Timothy Busfield, 55.
Busfield popped the question over the Christmas holiday, and on Monday the couple celebrated its impending nuptials during a lavish party at Mr. Chow in Los Angeles, a representative confirmed to UsMagazine.com.
A source says, "They got engaged over the holidays. They've known each other for quite some time, as their paths have crossed off-and-on over the past 20 years."
It will be the third marriage for both TV stars. The former "Little House on the Prairie" star and mother-of-two's exes include actor Bo Brinkman and Bruce Boxleitner, who she divorced in 2011.
Busfield, who has three children of his own, was previously wed to Radha Delmarter and Jenny Meriwin.
Gilbert most recently appeared on the 14th season of "Dancing With The Stars." Busfield has made appearances on several TV shows, including "Law & Order," "Blue Bloods," and "The Mob Doctor." He is most well known for his role in the 1980s series "Thirtysomething."