diff --git a/src/constraints/form/form_point_mass.jl b/src/constraints/form/form_point_mass.jl
index 6546edd44..42b400f12 100644
--- a/src/constraints/form/form_point_mass.jl
+++ b/src/constraints/form/form_point_mass.jl
@@ -73,6 +73,9 @@ ReactiveMP.constrain_form(pmconstraint::PointMassFormConstraint, distribution) =
 # There is no need to call the optimizer on a `Distribution` object since they should have a well defined `mode`
 ReactiveMP.constrain_form(::PointMassFormConstraint, distribution::Distribution) = PointMass(mode(distribution))
 
+# Except for the DirichletCollection. For this one, we will use the mean instead:
+ReactiveMP.constrain_form(::PointMassFormConstraint, distribution::DirichletCollection) = PointMass(mean(distribution))
+
 """
     default_point_mass_form_constraint_optimizer(::Type{<:VariateType}, ::Type{<:ValueSupport}, constraint::PointMassFormConstraint, distribution)
 
diff --git a/test/constraints/form/form_point_mass_tests.jl b/test/constraints/form/form_point_mass_tests.jl
index d94ac8638..1c14e85bc 100644
--- a/test/constraints/form/form_point_mass_tests.jl
+++ b/test/constraints/form/form_point_mass_tests.jl
@@ -125,4 +125,12 @@
             @test mean(result.posteriors[:θ]) ≈ p atol = 1e-1
         end
     end
+
+    Distributions.mode(d::DirichletCollection) = error("`mode` should not be called on DirichletCollection.")
+
+    @testset "`DirichletCollection` exception (mode is not defined)" begin
+        constraint = PointMassFormConstraint()
+        d = DirichletCollection(ones(3, 3))
+        opt = constrain_form(constraint, d)
+    end
 end