diff --git a/akka-javasdk-testkit/src/main/java/akka/javasdk/testkit/EventingTestKit.java b/akka-javasdk-testkit/src/main/java/akka/javasdk/testkit/EventingTestKit.java
index 8bedc5a8f..86b6e3223 100644
--- a/akka-javasdk-testkit/src/main/java/akka/javasdk/testkit/EventingTestKit.java
+++ b/akka-javasdk-testkit/src/main/java/akka/javasdk/testkit/EventingTestKit.java
@@ -44,18 +44,39 @@ interface IncomingMessages {
     /**
      * Simulate the publishing of a raw message.
      *
-     * @param message raw bytestring to be published
+     * @param message raw protobuf bytestring to be published
+     *
+     * @deprecated Use publish with byte array parameter
      */
+    @Deprecated
     void publish(ByteString message);
 
     /**
      * Simulate the publishing of a raw message.
      *
-     * @param message  raw bytestring to be published
+     * @param message  raw protobuf bytestring to be published
      * @param metadata associated with the message
+     *
+     * @deprecated Use publish with byte array parameter
      */
+    @Deprecated
     void publish(ByteString message, Metadata metadata);
 
+    /**
+     * Simulate the publishing of a raw message.
+     *
+     * @param message raw byte array to be published
+     */
+    void publish(byte[] message);
+
+    /**
+     * Simulate the publishing of a raw message.
+     *
+     * @param message  raw byte array to be published
+     * @param metadata associated with the message
+     */
+    void publish(byte[] message, Metadata metadata);
+
     /**
      * Simulate the publishing of a message.
      *
diff --git a/akka-javasdk-testkit/src/main/scala/akka/javasdk/testkit/impl/EventingTestKitImpl.scala b/akka-javasdk-testkit/src/main/scala/akka/javasdk/testkit/impl/EventingTestKitImpl.scala
index 2c684f7bc..2b31bf99e 100644
--- a/akka-javasdk-testkit/src/main/scala/akka/javasdk/testkit/impl/EventingTestKitImpl.scala
+++ b/akka-javasdk-testkit/src/main/scala/akka/javasdk/testkit/impl/EventingTestKitImpl.scala
@@ -302,6 +302,14 @@ private[testkit] class IncomingMessagesImpl(val sourcesHolder: ActorRef, val ser
     Await.result(addSource, 5.seconds)
   }
 
+  override def publish(message: Array[Byte]): Unit =
+    publish(message, SdkMetadata.EMPTY)
+
+  override def publish(message: Array[Byte], metadata: SdkMetadata): Unit = {
+    val addSource = sourcesHolder.ask(SourcesHolder.Publish(ByteString.copyFrom(message), metadata))(5.seconds)
+    Await.result(addSource, 5.seconds)
+  }
+
   override def publish(message: TestKitMessage[_]): Unit = message.getPayload match {
     case javaPb: GeneratedMessageV3 => publish(javaPb.toByteString, message.getMetadata)
     case scalaPb: GeneratedMessage  => publish(scalaPb.toByteString, message.getMetadata)
diff --git a/akka-javasdk-testkit/src/main/scala/akka/javasdk/testkit/impl/SourcesHolder.scala b/akka-javasdk-testkit/src/main/scala/akka/javasdk/testkit/impl/SourcesHolder.scala
index b58b9a840..ddffccbcc 100644
--- a/akka-javasdk-testkit/src/main/scala/akka/javasdk/testkit/impl/SourcesHolder.scala
+++ b/akka-javasdk-testkit/src/main/scala/akka/javasdk/testkit/impl/SourcesHolder.scala
@@ -17,8 +17,8 @@ import scala.collection.mutable.ArrayBuffer
 
 object SourcesHolder {
 
-  case class AddSource(runningSourceProbe: RunningSourceProbe)
-  case class Publish(message: ByteString, metadata: SdkMetadata)
+  final case class AddSource(runningSourceProbe: RunningSourceProbe)
+  final case class Publish(message: ByteString, metadata: SdkMetadata)
 }
 
 class SourcesHolder extends Actor {