diff --git a/csw-params/jvm/src/test/scala/csw/params/core/formats/JsonContractTest.scala b/csw-params/jvm/src/test/scala/csw/params/core/formats/JsonContractTest.scala
index 68227364ff..1821705696 100644
--- a/csw-params/jvm/src/test/scala/csw/params/core/formats/JsonContractTest.scala
+++ b/csw-params/jvm/src/test/scala/csw/params/core/formats/JsonContractTest.scala
@@ -127,10 +127,13 @@ class JsonContractTest extends AnyFunSpec with Matchers {
       val arrayDataParam = arrayDataKey.set(ArrayData.fromArray(a1), ArrayData.fromArrays[Byte](10, 20, 30, 40, 50))
 
       val systemEvent       = SystemEvent(eventId, prefix, eventName, eventTime, Set(arrayDataParam))
+      val systemEvent2      = SystemEvent(prefix, eventName, Set(arrayDataParam)).withEventTime(eventTime).copy(eventId = eventId)
       val systemEventToJson = JsonSupport.writeEvent(systemEvent)
+      val systemEventToJson2 = JsonSupport.writeEvent(systemEvent2)
 
       val expectedSystemEventJson = Json.parse(Source.fromResource("json/system_event.json").mkString)
       systemEventToJson shouldEqual expectedSystemEventJson
+      systemEventToJson2 shouldEqual expectedSystemEventJson
     }
   }
 
diff --git a/csw-params/shared/src/main/scala/csw/params/events/events.scala b/csw-params/shared/src/main/scala/csw/params/events/events.scala
index 111aac9263..fb1e497972 100644
--- a/csw-params/shared/src/main/scala/csw/params/events/events.scala
+++ b/csw-params/shared/src/main/scala/csw/params/events/events.scala
@@ -123,6 +123,12 @@ case class SystemEvent private[csw] (
    */
   override protected def create(data: Set[Parameter[?]]): SystemEvent =
     copy(eventId = Id(), eventTime = UTCTime.now(), paramSet = data)
+
+  /**
+   * Returns a new SystemEvent with the same values and the given time and a new id
+   */
+  def withEventTime(eventTime: UTCTime): SystemEvent =
+    copy(eventId = Id(), eventTime = eventTime)
 }
 
 object SystemEvent {