move.patch

diff --git a/assets/js/base/components/cart-checkout/address-form/address-form.tsx b/assets/js/base/components/cart-checkout/address-form/address-form.tsx
index cec368a6c..966ffeb06 100644
--- a/assets/js/base/components/cart-checkout/address-form/address-form.tsx
+++ b/assets/js/base/components/cart-checkout/address-form/address-form.tsx
@@ -144,6 +144,29 @@ const AddressForm = ( {
 
 	id = id || instanceId;
 
+	const customValidationHandler = (
+		inputObject: HTMLInputElement,
+		fieldName: { key: string }
+	) => {
+		if (
+			fieldName.key === 'postcode' &&
+			values.country &&
+			! isPostcode( {
+				postcode: values.postcode,
+				country: values.country,
+			} )
+		) {
+			inputObject.setCustomValidity(
+				__(
+					'Please enter a valid postcode',
+					'woo-gutenberg-products-block'
+				)
+			);
+			return false;
+		}
+		return true;
+	};
+
 	return (
 		<div id={ id } className="wc-block-components-address-form">
 			{ addressFormFields.map( ( field ) => {
@@ -214,32 +237,11 @@ const AddressForm = ( {
 					);
 				}
 
-				const customValidationHandler = (
-					inputObject: HTMLInputElement
-				) => {
-					if (
-						field.key === 'postcode' &&
-						values.country &&
-						! isPostcode( {
-							postcode: values.postcode,
-							country: values.country,
-						} )
-					) {
-						inputObject.setCustomValidity(
-							__(
-								'Please enter a valid postcode',
-								'woo-gutenberg-products-block'
-							)
-						);
-						return false;
-					}
-					return true;
-				};
-
 				return (
 					<ValidatedTextInput
 						key={ field.key }
 						id={ `${ id }-${ field.key }` }
+						fieldName={ field.key }
 						errorId={ errorId }
 						className={ `wc-block-components-address-form__${ field.key }` }
 						label={
diff --git a/packages/checkout/components/text-input/validated-text-input.tsx b/packages/checkout/components/text-input/validated-text-input.tsx
index fc8f836a7..bbfc51c3e 100644
--- a/packages/checkout/components/text-input/validated-text-input.tsx
+++ b/packages/checkout/components/text-input/validated-text-input.tsx
@@ -52,8 +52,12 @@ interface ValidatedTextInputProps
 	errorMessage?: string | undefined;
 	// Custom validation function that is run on change. Use setCustomValidity to set an error message.
 	customValidation?:
-		| ( ( inputObject: HTMLInputElement ) => boolean )
+		| ( (
+				inputObject: HTMLInputElement,
+				fieldName: { key: string }
+		  ) => boolean )
 		| undefined;
+	fieldName: string;
 }
 
 const ValidatedTextInput = ( {
@@ -69,6 +73,7 @@ const ValidatedTextInput = ( {
 	value = '',
 	customValidation,
 	label,
+	fieldName,
 	...rest
 }: ValidatedTextInputProps ): JSX.Element => {
 	const [ isPristine, setIsPristine ] = useState( true );
@@ -106,7 +111,8 @@ const ValidatedTextInput = ( {
 			}
 
 			const inputIsValid = customValidation
-				? inputObject.checkValidity() && customValidation( inputObject )
+				? inputObject.checkValidity() &&
+				  customValidation( inputObject, fieldName )
 				: inputObject.checkValidity();
 
 			if ( inputIsValid ) {
@@ -130,6 +136,7 @@ const ValidatedTextInput = ( {
 			errorIdString,
 			setValidationErrors,
 			label,
+			fieldName,
 		]
 	);