diff --git a/plugins/woocommerce/client/legacy/css/_mixins.scss b/plugins/woocommerce/client/legacy/css/_mixins.scss
index 84812d62807..21152882ef8 100644
--- a/plugins/woocommerce/client/legacy/css/_mixins.scss
+++ b/plugins/woocommerce/client/legacy/css/_mixins.scss
@@ -319,3 +319,11 @@
 	font-size: 0.75em;
 	margin-top: 8px;
 }
+
+@mixin checkout-inline-error-message() {
+	color: var(--wc-red);
+	font-size: 0.75em;
+	line-height: 1.3;
+	margin-bottom: 0;
+	margin-top: 0.5em;
+}