diff --git a/src/Engine/ExecutionState.php b/src/Engine/ExecutionState.php
index 49647742..e9860f08 100644
--- a/src/Engine/ExecutionState.php
+++ b/src/Engine/ExecutionState.php
@@ -99,10 +99,12 @@ public function setVariableData($name, TypedDataInterface $data) {
    * {@inheritdoc}
    */
   public function getVariable($name) {
-    if (!$this->hasVariable($name)) {
-      throw new EvaluationException("Unable to get variable $name, it is not defined.");
+    try {
+      return $this->variables[$name];
+    }
+    catch (InvalidArgumentException $e) {
+      throw new EvaluationException($e->getMessage(), 0, $e);
     }
-    return $this->variables[$name];
   }
 
   /**