diff --git a/django/db/models/fields/related.py b/django/db/models/fields/related.py
index aa232c07f39..dfe9a8b81f2 100644
--- a/django/db/models/fields/related.py
+++ b/django/db/models/fields/related.py
@@ -618,7 +618,7 @@ class ManyToManyField(RelatedField, Field):
             msg = gettext_lazy('Separate multiple IDs with commas.')
         else:
             msg = gettext_lazy('Hold down "Control", or "Command" on a Mac, to select more than one.')
-        self.help_text = string_concat(self.help_text, msg)
+        self.help_text = string_concat(self.help_text, ' ', msg)
 
     def get_manipulator_field_objs(self):
         if self.rel.raw_id_admin: