diff --git a/src/Assets/Asset.php b/src/Assets/Asset.php
index ab82dcb..dee33ea 100644
--- a/src/Assets/Asset.php
+++ b/src/Assets/Asset.php
@@ -403,16 +403,41 @@ public function call_after_enqueue( $callable ) {
 
 	/**
 	 * Adds a wp_localize_script object to the asset.
+	 * If the object already exists, updates it with the new data.
 	 *
 	 * @since 1.0.0
+	 * @since TBD Add a conditional and support for updating existing objects.
+	 *
+	 * @param string $object_name     JS object name.
+	 * @param array  $data            Data to be assigned to the JS object.
+	 * @param bool   $force_overwrite Whether to force the overwrite of the object.
+	 *
+	 * @return static
+	 */
+	public function add_localize_script( string $object_name, array $data, $force_overwrite = false ) {
+		if ( $force_overwrite || ! isset( $this->wp_localize_script_objects[ $object_name ] ) ) {
+			$this->wp_localize_script_objects[ $object_name ] = $data;
+			return $this;
+		}
+
+		return $this->update_localize_script( $object_name, $data );
+	}
+
+	/**
+	 * Updates a wp_localize_script object with new data.
+	 *
+	 * @since TBD
 	 *
 	 * @param string $object_name JS object name.
-	 * @param array  $data        Data assigned to the JS object.
+	 * @param array  $data        Data to be assigned to the JS object.
 	 *
 	 * @return static
 	 */
-	public function add_localize_script( string $object_name, array $data ) {
-		$this->wp_localize_script_objects[ $object_name ] = $data;
+	public function update_localize_script( string $object_name, array $data ) {
+		$this->wp_localize_script_objects[ $object_name ] = array_merge_recursive(
+			$this->wp_localize_script_objects[ $object_name ],
+			$data
+		);
 		return $this;
 	}
 
diff --git a/src/Assets/Assets.php b/src/Assets/Assets.php
index fb0da65..c372561 100755
--- a/src/Assets/Assets.php
+++ b/src/Assets/Assets.php
@@ -190,7 +190,7 @@ public function filter_add_localization_data( $tag, $handle ) {
 		$wp_scripts->print_extra_script( $asset->get_slug(), true );
 		$localization_html = ob_get_clean();
 
-		// After printing it remove data;|
+		// After printing it remove data;
 		$wp_scripts->add_data( $asset->get_slug(), 'data', '' );
 
 		return $localization_html . $tag;
diff --git a/tests/acceptance/EnqueueJSCest.php b/tests/acceptance/EnqueueJSCest.php
index 1aac8a3..58f5563 100644
--- a/tests/acceptance/EnqueueJSCest.php
+++ b/tests/acceptance/EnqueueJSCest.php
@@ -216,34 +216,4 @@ public function it_should_be_a_module( AcceptanceTester $I ) {
 		$I->amOnPage( '/' );
 		$I->seeElement( '#fake-js-js[type=module]' );
 	}
-
-	public function it_should_localize( AcceptanceTester $I ) {
-		$code = file_get_contents( codecept_data_dir( 'enqueue-template.php' ) );
-		$code .= <<<PHP
-		add_action( 'wp_enqueue_scripts', function() {
-			Asset::add( 'fake-js', 'fake.js' )
-				->enqueue_on( 'wp_enqueue_scripts' )
-				->add_localize_script(
-					'animal',
-					[
-						'cow' => 'true',
-					]
-				)
-				->add_localize_script(
-					'color',
-					[ 'blue' ]
-				)
-				->register();
-		}, 100 );
-		PHP;
-
-		$I->haveMuPlugin( 'enqueue.php', $code );
-
-
-		$I->amOnPage( '/' );
-		$I->seeElement( '#fake-js-js-extra' );
-		$contents = $I->grabTextFrom( '#fake-js-js-extra' );
-		Assert::assertContains( 'var animal', $contents );
-		Assert::assertContains( 'var color', $contents );
-	}
 }
diff --git a/tests/acceptance/LocalizeJSCest.php b/tests/acceptance/LocalizeJSCest.php
new file mode 100644
index 0000000..f857f4b
--- /dev/null
+++ b/tests/acceptance/LocalizeJSCest.php
@@ -0,0 +1,160 @@
+<?php
+namespace StellarWP\Assets\Tests;
+
+use AcceptanceTester;
+use PHPUnit\Framework\Assert;
+
+class LocalizeJSCest {
+
+	public function it_should_localize( AcceptanceTester $I ) {
+		$code = file_get_contents( codecept_data_dir( 'enqueue-template.php' ) );
+		$code .= <<<PHP
+		add_action( 'wp_enqueue_scripts', function() {
+			Asset::add( 'fake-js', 'fake.js' )
+				->enqueue_on( 'wp_enqueue_scripts' )
+				->add_localize_script(
+					'animal',
+					[
+						'cow' => 'true',
+					]
+				)
+				->add_localize_script(
+					'color',
+					[ 'blue' ]
+				)
+				->register();
+		}, 100 );
+		PHP;
+
+		$I->haveMuPlugin( 'enqueue.php', $code );
+
+
+		$I->amOnPage( '/' );
+		$I->seeElement( '#fake-js-js-extra' );
+		$contents = $I->grabTextFrom( '#fake-js-js-extra' );
+		Assert::assertContains( 'var animal', $contents );
+		Assert::assertContains( 'var color', $contents );
+	}
+
+	public function immediate_localize_should_append( AcceptanceTester $I ) {
+		$code = file_get_contents( codecept_data_dir( 'enqueue-template.php' ) );
+		$code .= <<<PHP
+		add_action( 'wp_enqueue_scripts', function() {
+			Asset::add( 'fake-js', 'fake.js' )
+				->enqueue_on( 'wp_enqueue_scripts' )
+				->add_localize_script(
+					'animal',
+					[
+						'cow' => 'black',
+					]
+				)
+				->add_localize_script(
+					'color',
+					[ 'blue' ]
+				)
+				->add_localize_script(
+					'animal',
+					[
+						'cow' => 'brown',
+					]
+				)
+				->register();
+		}, 100 );
+		PHP;
+
+		$I->haveMuPlugin( 'enqueue.php', $code );
+
+
+		$I->amOnPage( '/' );
+		$I->seeElement( '#fake-js-js-extra' );
+		$contents = $I->grabTextFrom( '#fake-js-js-extra' );
+		Assert::assertContains( 'var animal', $contents );
+		Assert::assertContains( 'var color', $contents );
+		Assert::assertContains( 'brown', $contents );
+		Assert::assertContains( 'black', $contents );
+	}
+
+	public function it_should_overwrite_localize_with_force( AcceptanceTester $I ) {
+		$code = file_get_contents( codecept_data_dir( 'enqueue-template.php' ) );
+		$code .= <<<PHP
+		add_action( 'wp_enqueue_scripts', function() {
+			Asset::add( 'fake-js', 'fake.js' )
+				->enqueue_on( 'wp_enqueue_scripts' )
+				->add_localize_script(
+					'animal',
+					[
+						'cow' => 'black',
+					]
+				)
+				->add_localize_script(
+					'color',
+					[ 'blue' ]
+				)
+				->add_localize_script(
+					'animal',
+					[
+						'cow' => 'brown',
+					],
+					true
+				)
+				->register();
+		}, 100 );
+		PHP;
+
+		$I->haveMuPlugin( 'enqueue.php', $code );
+
+
+		$I->amOnPage( '/' );
+		$I->seeElement( '#fake-js-js-extra' );
+		$contents = $I->grabTextFrom( '#fake-js-js-extra' );
+		Assert::assertContains( 'var animal', $contents );
+		Assert::assertContains( 'var color', $contents );
+		Assert::assertContains( 'brown', $contents );
+		Assert::assertNotContains( 'black', $contents );
+	}
+
+	public function it_should_append_to_localize_with_same_handle( AcceptanceTester $I ) {
+		$code_base = file_get_contents( codecept_data_dir( 'enqueue-template.php' ) );
+		$code = $code_base . <<<PHP
+		add_action( 'wp_enqueue_scripts', function() {
+			Asset::add( 'fake-js', 'fake.js' )
+				->enqueue_on( 'wp_enqueue_scripts' )
+				->add_localize_script(
+					'animal',
+					[
+						'cow' => 'true',
+					]
+				)
+				->add_localize_script(
+					'color',
+					[ 'blue' ]
+				)
+				->register();
+		}, 100 );
+		PHP;
+
+		$I->haveMuPlugin( 'enqueue.php', $code );
+
+		$code_2 = $code_base . <<<PHP
+		add_action( 'wp_enqueue_scripts', function() {
+			Assets::get( 'fake-js' )
+				->add_localize_script(
+					'animal',
+						[
+							'sheep' => 'true',
+						]
+				);
+		}, 110 );
+		PHP;
+
+		$I->haveMuPlugin( 'enqueue_2.php', $code_2 );
+
+		$I->amOnPage( '/' );
+		$I->seeElement( '#fake-js-js-extra' );
+		$contents = $I->grabTextFrom( '#fake-js-js-extra' );
+		Assert::assertContains( 'var animal', $contents );
+		Assert::assertContains( 'var color', $contents );
+		Assert::assertContains( 'cow', $contents );
+		Assert::assertContains( 'sheep', $contents );
+	}
+}