Masterson, 44, is best known for her work in the films "Some Kind of Wonderful," "Benny & Joon" and "Bed of Roses." She married Davidson in 2006.
"My family life at home in Brooklyn is becoming (more involved) -- we're actually pregnant with twins," Davidson, star of TV's "Army Wives," told E! News Tuesday. "We are four months along. So balancing career and family is becoming increasingly challenging for me … and in five months we are going to have three kids under the age of two. We are in happy shock about it."