After just two and half weeks of release, the Sydney Sweeney box-office hit “The Housemaid” is getting a sequel. Lionsgate announced Tuesday that it will start production on “The Housemaid’s Secret” later this year. The film will be based on the second of Freida McFadden’s bestselling trilogy of books. “The Housemaid” has been a hit at the holiday box office, grossing more than $75 million and $133 million worldwide in 17 days. The film has handed Sweeney a major box-office victory after a disappointing result for her awards-hopeful “Christy” in November. That film grossed just $2 million worldwide.