The church of Heks was rebuilt from 25 June 1850 on the site of an older building. This new building got a new orientation with the west facade and the main entrance on the side of the castle park. The neoclassical church building has a sober exterior with a decorative accent on the west facade with its tower crowning.
In contrast to the exterior, the plastered interior of the church accentuates the choir, whose heavy decoration is built around a central representation of the Assumption of Virgin Mary designed by J. Delbove. The chateau lords financed the decoration and have their own crypt and oratory adjoining the choir, separated from it by a framework of stained-glass windows in which their family coat of arms is incorporated.
The de Marchant et d'Ansembourg family also contributed significantly to the furnishing of the church (confessionals, pulpit, organ).