diff --git a/blocklanguages-header.tpl b/blocklanguages-header.tpl
new file mode 100644
index 0000000..d0fdb3d
--- /dev/null
+++ b/blocklanguages-header.tpl
@@ -0,0 +1,10 @@
+{foreach from=$languages key=k item=language name="languages"}
+    {if $language.iso_code != $lang_iso}
+        {assign var=indice_lang value=$language.id_lang}
+        {if isset($lang_rewrite_urls.$indice_lang)}
+            <link rel="alternate" hreflang="{$language.iso_code|escape:'html':'UTF-8'}" href="{$lang_rewrite_urls.$indice_lang|escape:'html':'UTF-8'}">
+        {else}
+            <link rel="alternate" hreflang="{$language.iso_code|escape:'html':'UTF-8'}" href="{$link->getLanguageLink($language.id_lang)|escape:'html':'UTF-8'}">
+        {/if}
+    {/if}
+{/foreach}
diff --git a/blocklanguages.php b/blocklanguages.php
index 02031b6..e571230 100644
--- a/blocklanguages.php
+++ b/blocklanguages.php
@@ -51,37 +51,40 @@ public function install()
 
 	protected function _prepareHook($params)
 	{
+		static $default_rewrite;
 		$languages = Language::getLanguages(true, $this->context->shop->id);
 		if (!count($languages))
 			return false;
-		$link = new Link();
-
 		if ((int)Configuration::get('PS_REWRITING_SETTINGS'))
 		{
-			$default_rewrite = array();
-			if (Dispatcher::getInstance()->getController() == 'product' && ($id_product = (int)Tools::getValue('id_product')))
-			{
-				$rewrite_infos = Product::getUrlRewriteInformations((int)$id_product);
-				foreach ($rewrite_infos as $infos)
-					$default_rewrite[$infos['id_lang']] = $link->getProductLink((int)$id_product, $infos['link_rewrite'], $infos['category_rewrite'], $infos['ean13'], (int)$infos['id_lang']);
-			}
+			if (!is_array($default_rewrite)) {
+				$link = new Link();
 
-			if (Dispatcher::getInstance()->getController() == 'category' && ($id_category = (int)Tools::getValue('id_category')))
-			{
-				$rewrite_infos = Category::getUrlRewriteInformations((int)$id_category);
-				foreach ($rewrite_infos as $infos)
-					$default_rewrite[$infos['id_lang']] = $link->getCategoryLink((int)$id_category, $infos['link_rewrite'], $infos['id_lang']);
-			}
+				$default_rewrite = array();
+				if (Dispatcher::getInstance()->getController() == 'product' && ($id_product = (int)Tools::getValue('id_product')))
+				{
+					$rewrite_infos = Product::getUrlRewriteInformations((int)$id_product);
+					foreach ($rewrite_infos as $infos)
+						$default_rewrite[$infos['id_lang']] = $link->getProductLink((int)$id_product, $infos['link_rewrite'], $infos['category_rewrite'], $infos['ean13'], (int)$infos['id_lang']);
+				}
+
+				if (Dispatcher::getInstance()->getController() == 'category' && ($id_category = (int)Tools::getValue('id_category')))
+				{
+					$rewrite_infos = Category::getUrlRewriteInformations((int)$id_category);
+					foreach ($rewrite_infos as $infos)
+						$default_rewrite[$infos['id_lang']] = $link->getCategoryLink((int)$id_category, $infos['link_rewrite'], $infos['id_lang']);
+				}
 
-			if (Dispatcher::getInstance()->getController() == 'cms' && (($id_cms = (int)Tools::getValue('id_cms')) || ($id_cms_category = (int)Tools::getValue('id_cms_category'))))
-			{
-				$rewrite_infos = (isset($id_cms) && !isset($id_cms_category)) ? CMS::getUrlRewriteInformations($id_cms) : CMSCategory::getUrlRewriteInformations($id_cms_category);
-				foreach ($rewrite_infos as $infos)
+				if (Dispatcher::getInstance()->getController() == 'cms' && (($id_cms = (int)Tools::getValue('id_cms')) || ($id_cms_category = (int)Tools::getValue('id_cms_category'))))
 				{
-					$arr_link = (isset($id_cms) && !isset($id_cms_category)) ?
-						$link->getCMSLink($id_cms, $infos['link_rewrite'], null, $infos['id_lang']) :
-						$link->getCMSCategoryLink($id_cms_category, $infos['link_rewrite'], $infos['id_lang']);
-					$default_rewrite[$infos['id_lang']] = $arr_link;
+					$rewrite_infos = (isset($id_cms) && !isset($id_cms_category)) ? CMS::getUrlRewriteInformations($id_cms) : CMSCategory::getUrlRewriteInformations($id_cms_category);
+					foreach ($rewrite_infos as $infos)
+					{
+						$arr_link = (isset($id_cms) && !isset($id_cms_category)) ?
+							$link->getCMSLink($id_cms, $infos['link_rewrite'], null, $infos['id_lang']) :
+							$link->getCMSCategoryLink($id_cms_category, $infos['link_rewrite'], $infos['id_lang']);
+						$default_rewrite[$infos['id_lang']] = $arr_link;
+					}
 				}
 			}
 			$this->smarty->assign('lang_rewrite_urls', $default_rewrite);
@@ -97,9 +100,9 @@ protected function _prepareHook($params)
 	*/
 	public function hookDisplayTop($params)
 	{
-		if (!$this->_prepareHook($params))
-			return;
-		return $this->display(__FILE__, 'blocklanguages.tpl');
+		if ($this->_prepareHook($params)) {
+            return $this->display(__FILE__, 'blocklanguages.tpl');
+        }
 	}
 
 	public function hookDisplayNav($params)
@@ -111,6 +114,9 @@ public function hookDisplayNav($params)
 	public function hookDisplayHeader($params)
 	{
 		$this->context->controller->addCSS($this->_path.'blocklanguages.css', 'all');
+		if ($this->_prepareHook($params)) {
+            return $this->display(__FILE__, 'blocklanguages-header.tpl');
+        }
 	}
 }