The French-Irish coproduction will be Merlet's first feature since her 1997 award-winning biography Artemisia. The film will shoot in Ireland this summer.
Van Houten is playing the lead role of an Irish doctor who investigates a mysterious case of a child that almost died in the care of a babysitter. The search leads her into a religious community of extreme believers.
Dorothy Mills will be Van Houten's international film debut after she came to acclaim in Paul Verhoeven's Dutch wartime thriller Black Book.
No co-stars have been announced yet. Dorothy Mills is produced by France's Fidelite Films, with support from Eurimages.
Van Houten also appeared in earlier Dutch features such as Bonkers by Martin Koolhoven, Father's Affair by Maarten Treurniet and Undercover Kitty by Vincent Bal.