diff --git a/logstash-core/src/main/java/org/logstash/ext/JrubyTimestampExtLibrary.java b/logstash-core/src/main/java/org/logstash/ext/JrubyTimestampExtLibrary.java
index 58a58eaad..50e3532db 100644
--- a/logstash-core/src/main/java/org/logstash/ext/JrubyTimestampExtLibrary.java
+++ b/logstash-core/src/main/java/org/logstash/ext/JrubyTimestampExtLibrary.java
@@ -1,5 +1,6 @@
 package org.logstash.ext;
 
+import com.fasterxml.jackson.databind.annotation.JsonSerialize;
 import java.io.IOException;
 import org.jruby.Ruby;
 import org.jruby.RubyClass;
@@ -19,6 +20,7 @@ import org.jruby.runtime.ThreadContext;
 import org.jruby.runtime.builtin.IRubyObject;
 import org.jruby.runtime.load.Library;
 import org.logstash.Timestamp;
+import org.logstash.json.RubyTimestampSerializer;
 
 public class JrubyTimestampExtLibrary implements Library {
 
@@ -40,6 +42,7 @@ public class JrubyTimestampExtLibrary implements Library {
     }
 
     @JRubyClass(name = "Timestamp")
+    @JsonSerialize(using = RubyTimestampSerializer.class)
     public static class RubyTimestamp extends RubyObject {
 
         private Timestamp timestamp;
diff --git a/logstash-core/src/main/java/org/logstash/json/RubyTimestampSerializer.java b/logstash-core/src/main/java/org/logstash/json/RubyTimestampSerializer.java
new file mode 100644
index 000000000..935db8dd8
--- /dev/null
+++ b/logstash-core/src/main/java/org/logstash/json/RubyTimestampSerializer.java
@@ -0,0 +1,22 @@
+package org.logstash.json;
+
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.databind.JsonSerializer;
+import com.fasterxml.jackson.databind.SerializerProvider;
+import java.io.IOException;
+import org.logstash.ext.JrubyTimestampExtLibrary;
+
+/**
+ * Serializer for {@link JrubyTimestampExtLibrary.RubyTimestamp} that serializes it exactly the same
+ * way {@link TimestampSerializer} serializes {@link org.logstash.Timestamp} to ensure consistent
+ * serialization across Java and Ruby representation of {@link org.logstash.Timestamp}.
+ */
+public final class RubyTimestampSerializer
+    extends JsonSerializer<JrubyTimestampExtLibrary.RubyTimestamp> {
+
+    @Override
+    public void serialize(final JrubyTimestampExtLibrary.RubyTimestamp value,
+        final JsonGenerator jgen, final SerializerProvider provider) throws IOException {
+        jgen.writeString(value.getTimestamp().toIso8601());
+    }
+}
diff --git a/logstash-core/src/test/java/org/logstash/EventTest.java b/logstash-core/src/test/java/org/logstash/EventTest.java
index efc8b8978..7059b6fee 100644
--- a/logstash-core/src/test/java/org/logstash/EventTest.java
+++ b/logstash-core/src/test/java/org/logstash/EventTest.java
@@ -6,6 +6,7 @@ import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import org.jruby.RubyTime;
 import org.junit.Test;
 
 import static net.javacrumbs.jsonunit.JsonAssert.assertJsonEquals;
@@ -106,6 +107,19 @@ public final class EventTest {
         assertJsonEquals("{\"@timestamp\":\"" + e.getTimestamp().toIso8601() + "\",\"foo\":{\"0\":{\"baz\":1}},\"@version\":\"1\"}", e.toJson());
     }
 
+    @Test
+    public void testTimestampFieldToJson() throws Exception {
+        Event e = new Event();
+        final RubyTime time = RubyUtil.RUBY.newTime(1000L);
+        e.setField("[foo][bar][baz]", time);
+        assertJsonEquals(
+            String.format(
+                "{\"@timestamp\":\"%s\",\"foo\":{\"bar\":{\"baz\":\"%s\"}},\"@version\":\"1\"}",
+                e.getTimestamp().toIso8601(), new Timestamp(time.getDateTime()).toIso8601()
+            ), e.toJson()
+        );
+    }
+
     @Test
     public void testGetFieldList() throws Exception {
         Map<String, Object> data = new HashMap<>();