diff --git a/app/javascript/mastodon/locales/defaultMessages.json b/app/javascript/mastodon/locales/defaultMessages.json
index 1e7fef6be..7e8447e4f 100644
--- a/app/javascript/mastodon/locales/defaultMessages.json
+++ b/app/javascript/mastodon/locales/defaultMessages.json
@@ -132,6 +132,31 @@
     ],
     "path": "app/javascript/mastodon/components/missing_indicator.json"
   },
+  {
+    "descriptors": [
+      {
+        "defaultMessage": "now",
+        "id": "relative_time.just_now"
+      },
+      {
+        "defaultMessage": "{number}s",
+        "id": "relative_time.seconds"
+      },
+      {
+        "defaultMessage": "{number}m",
+        "id": "relative_time.minutes"
+      },
+      {
+        "defaultMessage": "{number}h",
+        "id": "relative_time.hours"
+      },
+      {
+        "defaultMessage": "{number}d",
+        "id": "relative_time.days"
+      }
+    ],
+    "path": "app/javascript/mastodon/components/relative_timestamp.json"
+  },
   {
     "descriptors": [
       {
diff --git a/app/javascript/mastodon/locales/ja.json b/app/javascript/mastodon/locales/ja.json
index 11356c6db..ce797a7c7 100644
--- a/app/javascript/mastodon/locales/ja.json
+++ b/app/javascript/mastodon/locales/ja.json
@@ -160,6 +160,11 @@
   "privacy.public.short": "公開",
   "privacy.unlisted.long": "公開TLで表示しない",
   "privacy.unlisted.short": "未収載",
+  "relative_time.days": "{number}日前",
+  "relative_time.hours": "{number}時間前",
+  "relative_time.just_now": "今",
+  "relative_time.minutes": "{number}分前",
+  "relative_time.seconds": "{number}秒前",
   "reply_indicator.cancel": "キャンセル",
   "report.placeholder": "コメント",
   "report.submit": "通報する",