diff --git a/src/components/footer/_macro.njk b/src/components/footer/_macro.njk
index 887959c144..21df8d3093 100644
--- a/src/components/footer/_macro.njk
+++ b/src/components/footer/_macro.njk
@@ -30,7 +30,7 @@
                             onsButton({
                                 "id": params.button.id,
                                 "type": params.button.type,
-                                "classes": "btn--ghost-blue" + (" " + params.button.classes if params.button.classes),
+                                "classes": "btn--ghost-blue" + (" " + params.button.classes if params.button.classes else ""),
                                 "text": params.button.text,
                                 "html": params.button.html,
                                 "name": params.button.name,