diff --git a/moment/moment-external-tests.ts b/moment/moment-external-tests.ts
index ed3e1e2a82..c8108d1b99 100644
--- a/moment/moment-external-tests.ts
+++ b/moment/moment-external-tests.ts
@@ -255,6 +255,7 @@ moment.locale('en', {
     weekdaysShort: ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"],
     weekdaysMin: ["Su", "Mo", "Tu", "We", "Th", "Fr", "Sa"],
     longDateFormat: {
+        LTS: "h:mm:ss A",
         LT: "h:mm A",
         L: "MM/DD/YYYY",
         LL: "MMMM D YYYY",
@@ -376,6 +377,7 @@ moment.locale('en', {
 
 moment.locale('en', {
     longDateFormat : {
+        LTS: "h:mm:ss A",
         LT: "h:mm A",
         L: "MM/DD/YYYY",
         l: "M/D/YYYY",
@@ -390,6 +392,7 @@ moment.locale('en', {
 
 moment.locale('en', {
     longDateFormat : {
+        LTS: "h:mm:ss A",
         LT: "h:mm A",
         L: "MM/DD/YYYY",
         LL: "MMMM Do YYYY",
diff --git a/moment/moment-tests.ts b/moment/moment-tests.ts
index 67724068f5..26b2f1d0f6 100644
--- a/moment/moment-tests.ts
+++ b/moment/moment-tests.ts
@@ -257,6 +257,7 @@ moment.locale('en', {
     weekdaysShort: ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"],
     weekdaysMin: ["Su", "Mo", "Tu", "We", "Th", "Fr", "Sa"],
     longDateFormat: {
+        LTS: "h:mm:ss A",
         LT: "h:mm A",
         L: "MM/DD/YYYY",
         LL: "MMMM D YYYY",