diff --git a/app/src/main/res/values-cs/strings.xml b/app/src/main/res/values-cs/strings.xml
index f3208885a..ccce1efc0 100644
--- a/app/src/main/res/values-cs/strings.xml
+++ b/app/src/main/res/values-cs/strings.xml
@@ -495,4 +495,5 @@
   <string name="set_compact_mode">Compact mode</string>
   <string name="set_share_details">Add toot details when sharing</string>
   <string name="support_the_app_on_liberapay">Support the app on Liberapay</string>
+  <string name="alert_regex">There is an error in the regular expression!</string>
 </resources>