diff --git a/gtsam/discrete/discrete.i b/gtsam/discrete/discrete.i
index a25897ffa..78efd57e2 100644
--- a/gtsam/discrete/discrete.i
+++ b/gtsam/discrete/discrete.i
@@ -82,6 +82,7 @@ virtual class DecisionTreeFactor : gtsam::DiscreteFactor {
 };
 
 #include <gtsam/discrete/DiscreteConditional.h>
+#include <gtsam/hybrid/HybridValues.h>
 virtual class DiscreteConditional : gtsam::DecisionTreeFactor {
   DiscreteConditional();
   DiscreteConditional(size_t nFrontals, const gtsam::DecisionTreeFactor& f);
@@ -95,9 +96,12 @@ virtual class DiscreteConditional : gtsam::DecisionTreeFactor {
   DiscreteConditional(const gtsam::DecisionTreeFactor& joint,
                       const gtsam::DecisionTreeFactor& marginal,
                       const gtsam::Ordering& orderedKeys);
+
+  // Standard interface
+  double logNormalizationConstant() const;
   double logProbability(const gtsam::DiscreteValues& values) const;
   double evaluate(const gtsam::DiscreteValues& values) const;
-  double operator()(const gtsam::DiscreteValues& values) const;
+  double error(const gtsam::DiscreteValues& values) const;
   gtsam::DiscreteConditional operator*(
       const gtsam::DiscreteConditional& other) const;
   gtsam::DiscreteConditional marginal(gtsam::Key key) const;
@@ -119,6 +123,8 @@ virtual class DiscreteConditional : gtsam::DecisionTreeFactor {
   size_t sample(size_t value) const;
   size_t sample() const;
   void sampleInPlace(gtsam::DiscreteValues @parentsValues) const;
+
+  // Markdown and HTML
   string markdown(const gtsam::KeyFormatter& keyFormatter =
                       gtsam::DefaultKeyFormatter) const;
   string markdown(const gtsam::KeyFormatter& keyFormatter,
@@ -127,6 +133,11 @@ virtual class DiscreteConditional : gtsam::DecisionTreeFactor {
                   gtsam::DefaultKeyFormatter) const;
   string html(const gtsam::KeyFormatter& keyFormatter,
               std::map<gtsam::Key, std::vector<std::string>> names) const;
+
+  // Expose HybridValues versions
+  double logProbability(const gtsam::HybridValues& x) const;
+  double evaluate(const gtsam::HybridValues& x) const;
+  double error(const gtsam::HybridValues& x) const;
 };
 
 #include <gtsam/discrete/DiscreteDistribution.h>
diff --git a/gtsam/hybrid/hybrid.i b/gtsam/hybrid/hybrid.i
index aad1cca9b..bbadd1aa8 100644
--- a/gtsam/hybrid/hybrid.i
+++ b/gtsam/hybrid/hybrid.i
@@ -61,6 +61,7 @@ virtual class HybridConditional {
   size_t nrParents() const;
 
   // Standard interface:
+  double logNormalizationConstant() const;
   double logProbability(const gtsam::HybridValues& values) const;
   double evaluate(const gtsam::HybridValues& values) const;
   double operator()(const gtsam::HybridValues& values) const;
diff --git a/gtsam/linear/linear.i b/gtsam/linear/linear.i
index 2d88c5f93..c0230f1c2 100644
--- a/gtsam/linear/linear.i
+++ b/gtsam/linear/linear.i
@@ -456,6 +456,7 @@ class GaussianFactorGraph {
 };
 
 #include <gtsam/linear/GaussianConditional.h>
+#include <gtsam/hybrid/HybridValues.h>
 virtual class GaussianConditional : gtsam::JacobianFactor {
   // Constructors
   GaussianConditional(size_t key, Vector d, Matrix R,
@@ -497,6 +498,7 @@ virtual class GaussianConditional : gtsam::JacobianFactor {
   bool equals(const gtsam::GaussianConditional& cg, double tol) const;
   
   // Standard Interface
+  double logNormalizationConstant() const;
   double logProbability(const gtsam::VectorValues& x) const;
   double evaluate(const gtsam::VectorValues& x) const;
   double error(const gtsam::VectorValues& x) const;
@@ -518,6 +520,11 @@ virtual class GaussianConditional : gtsam::JacobianFactor {
 
   // enabling serialization functionality
   void serialize() const;
+
+  // Expose HybridValues versions
+  double logProbability(const gtsam::HybridValues& x) const;
+  double evaluate(const gtsam::HybridValues& x) const;
+  double error(const gtsam::HybridValues& x) const;
 };
 
 #include <gtsam/linear/GaussianDensity.h>
diff --git a/python/gtsam/tests/test_HybridBayesNet.py b/python/gtsam/tests/test_HybridBayesNet.py
index c949551c4..01e1c5a5d 100644
--- a/python/gtsam/tests/test_HybridBayesNet.py
+++ b/python/gtsam/tests/test_HybridBayesNet.py
@@ -17,8 +17,8 @@ import numpy as np
 from gtsam.symbol_shorthand import A, X
 from gtsam.utils.test_case import GtsamTestCase
 
-from gtsam import (DiscreteConditional, DiscreteKeys, GaussianConditional,
-                   GaussianMixture, HybridBayesNet, HybridValues, noiseModel)
+from gtsam import (DiscreteConditional, DiscreteKeys, DiscreteValues, GaussianConditional,
+                   GaussianMixture, HybridBayesNet, HybridValues, noiseModel, VectorValues)
 
 
 class TestHybridBayesNet(GtsamTestCase):
@@ -53,9 +53,13 @@ class TestHybridBayesNet(GtsamTestCase):
 
         # Create values at which to evaluate.
         values = HybridValues()
-        values.insert(asiaKey, 0)
-        values.insert(X(0), [-6])
-        values.insert(X(1), [1])
+        continuous = VectorValues()
+        continuous.insert(X(0), [-6])
+        continuous.insert(X(1), [1])
+        values.insert(continuous)
+        discrete = DiscreteValues()
+        discrete[asiaKey] = 0
+        values.insert(discrete)
 
         conditionalProbability = conditional.evaluate(values.continuous())
         mixtureProbability = conditional0.evaluate(values.continuous())
@@ -68,6 +72,26 @@ class TestHybridBayesNet(GtsamTestCase):
         self.assertAlmostEqual(bayesNet.logProbability(values),
                                math.log(bayesNet.evaluate(values)))
 
+        # Check invariance for all conditionals:
+        self.check_invariance(bayesNet.at(0).asGaussian(), continuous)
+        self.check_invariance(bayesNet.at(0).asGaussian(), values)
+        self.check_invariance(bayesNet.at(0), values)
+        
+        self.check_invariance(bayesNet.at(1), values)
+
+        self.check_invariance(bayesNet.at(2).asDiscrete(), discrete)
+        self.check_invariance(bayesNet.at(2).asDiscrete(), values)
+        self.check_invariance(bayesNet.at(2), values)
+
+    def check_invariance(self, conditional, values):
+        """Check invariance for given conditional."""
+        probability = conditional.evaluate(values)
+        self.assertTrue(probability >= 0.0)
+        logProb = conditional.logProbability(values)
+        self.assertAlmostEqual(probability, np.exp(logProb))
+        expected = conditional.logNormalizationConstant() - conditional.error(values)
+        self.assertAlmostEqual(logProb, expected)
+
 
 if __name__ == "__main__":
     unittest.main()