diff --git a/nd4j/nd4j-backends/nd4j-api-parent/nd4j-api/src/main/java/org/nd4j/autodiff/samediff/internal/AbstractSession.java b/nd4j/nd4j-backends/nd4j-api-parent/nd4j-api/src/main/java/org/nd4j/autodiff/samediff/internal/AbstractSession.java
index 65191ea84..1b520e7aa 100644
--- a/nd4j/nd4j-backends/nd4j-api-parent/nd4j-api/src/main/java/org/nd4j/autodiff/samediff/internal/AbstractSession.java
+++ b/nd4j/nd4j-backends/nd4j-api-parent/nd4j-api/src/main/java/org/nd4j/autodiff/samediff/internal/AbstractSession.java
@@ -31,6 +31,7 @@ import org.nd4j.base.Preconditions;
 import org.nd4j.linalg.api.ops.impl.controlflow.compat.*;
 
 import java.util.*;
+import org.nd4j.linalg.factory.Nd4j;
 
 /**
  * Additional functionality to add:
@@ -193,8 +194,16 @@ public abstract class AbstractSession<T, O> {
                 }
 
                 if(required && (placeholderValues == null || !placeholderValues.containsKey(s))){
-                    throw new IllegalStateException("An input placeholder \"" + s + "\" is required to calculate the requested outputs," +
-                            " but a placeholder value was not provided");
+
+                    // Some Keras layers (like GRU) do different things depending on whether the model is training.
+                    // We provide this value directly.
+                    if(s.endsWith("keras_learning_phase")){
+                        placeholderValues.put(s, (T) Nd4j.scalar(training));
+                    } else {
+                        throw new IllegalStateException(
+                                "An input placeholder \"" + s + "\" is required to calculate the requested outputs," +
+                                        " but a placeholder value was not provided");
+                    }
                 }
             }
         }