diff --git a/src/Commanding/CommandProcessor.php b/src/Commanding/CommandProcessor.php
index 027e419..305a68b 100644
--- a/src/Commanding/CommandProcessor.php
+++ b/src/Commanding/CommandProcessor.php
@@ -240,13 +240,27 @@ public function __invoke(GenericJsonSchemaCommand $command)
             }
             [$eventName, $payload] = $event;
 
+            $metadata = [];
+
+            if (array_key_exists(2, $event)) {
+                $metadata = $event[2];
+                if (! is_array($metadata)) {
+                    throw new \RuntimeException(sprintf(
+                        'Event returned by aggregate of type %s while handling command %s contains additional metadata but metadata type is not array. Detected type is: %s',
+                        $this->aggregateType,
+                        $this->commandName,
+                        (is_object($metadata) ? get_class($metadata) : gettype($metadata))
+                    ));
+                }
+            }
+
             /** @var GenericJsonSchemaEvent $event */
             $event = $this->messageFactory->createMessageFromArray($eventName, [
                 'payload' => $payload,
-                'metadata' => [
+                'metadata' => array_merge([
                     '_causation_id' => $command->uuid()->toString(),
                     '_causation_name' => $this->commandName,
-                ],
+                ], $metadata),
             ]);
 
             $aggregate->recordThat($event);
diff --git a/tests/Commanding/CommandProcessorTest.php b/tests/Commanding/CommandProcessorTest.php
index 15dc5c1..4c9bac6 100644
--- a/tests/Commanding/CommandProcessorTest.php
+++ b/tests/Commanding/CommandProcessorTest.php
@@ -360,4 +360,73 @@ public function it_provides_context_using_context_provider()
             'context' => ['msg' => 'it works'],
         ], $event->payload());
     }
+
+    /**
+     * @test
+     */
+    public function it_adds_additional_metadata_to_event()
+    {
+        $eventMachine = new EventMachine();
+
+        $eventMachine->load(MessageDescription::class);
+        $eventMachine->load(CacheableUserDescription::class);
+
+        $container = $this->prophesize(ContainerInterface::class);
+
+        $eventMachine->initialize($container->reveal());
+
+        $config = $eventMachine->compileCacheableConfig();
+
+        $commandRouting = $config['compiledCommandRouting'];
+        $aggregateDescriptions = $config['aggregateDescriptions'];
+
+        $recordedEvents = [];
+
+        $eventStore = $this->prophesize(EventStore::class);
+
+        $eventStore->appendTo(new StreamName('event_stream'), Argument::any())->will(function ($args) use (&$recordedEvents) {
+            $recordedEvents = iterator_to_array($args[1]);
+        });
+
+        $processorDesc = $commandRouting[Command::REGISTER_USER];
+        $processorDesc['eventApplyMap'] = $aggregateDescriptions[Aggregate::USER]['eventApplyMap'];
+
+        $arFunc = $processorDesc['aggregateFunction'];
+
+        //Wrap ar function to add additional metadata for this test
+        $processorDesc['aggregateFunction'] = function (Message $registerUser) use ($arFunc): \Generator {
+            [$event] = iterator_to_array($arFunc($registerUser));
+            [$eventName, $payload] = $event;
+            yield [$eventName, $payload, ['additional' => 'metadata']];
+        };
+
+        $commandProcessor = CommandProcessor::fromDescriptionArrayAndDependencies(
+            $processorDesc,
+            $this->getMockedEventMessageFactory(),
+            $eventStore->reveal()
+        );
+
+        $userId = Uuid::uuid4()->toString();
+
+        $registerUser = $this->getMockedCommandMessageFactory()->createMessageFromArray(Command::REGISTER_USER, [
+            UserDescription::IDENTIFIER => $userId,
+            UserDescription::USERNAME => 'Alex',
+            UserDescription::EMAIL => 'contact@prooph.de',
+        ]);
+
+        $commandProcessor($registerUser);
+
+        self::assertCount(1, $recordedEvents);
+        /** @var GenericJsonSchemaEvent $event */
+        $event = $recordedEvents[0];
+        self::assertEquals(Event::USER_WAS_REGISTERED, $event->messageName());
+        self::assertEquals([
+            '_causation_id' => $registerUser->uuid()->toString(),
+            '_causation_name' => $registerUser->messageName(),
+            '_aggregate_version' => 1,
+            '_aggregate_id' => $userId,
+            '_aggregate_type' => 'User',
+            'additional' => 'metadata',
+        ], $event->metadata());
+    }
 }