diff --git a/Build/phpstan/Core12/phpstan-baseline.neon b/Build/phpstan/Core12/phpstan-baseline.neon
index c65db8c2..5e2a265a 100644
--- a/Build/phpstan/Core12/phpstan-baseline.neon
+++ b/Build/phpstan/Core12/phpstan-baseline.neon
@@ -60,11 +60,6 @@ parameters:
 			count: 1
 			path: ../../../Classes/Hooks/ButtonBarHook.php
 
-		-
-			message: "#^There is no aspect \"frontend\\.preview\" configured so we can't figure out the exact type to return when calling TYPO3\\\\CMS\\\\Core\\\\Context\\\\Context\\:\\:getPropertyFromAspect$#"
-			count: 1
-			path: ../../../Classes/Hooks/DeeplPreviewFlagGeneratePageHook.php
-
 		-
 			message: "#^Parameter \\#1 \\$uid of method WebVision\\\\Deepltranslate\\\\Core\\\\Domain\\\\Repository\\\\GlossaryEntryRepository\\:\\:findEntryByUid\\(\\) expects int, int\\|string given\\.$#"
 			count: 1
diff --git a/Build/phpstan/Core12/phpstan.neon b/Build/phpstan/Core12/phpstan.neon
index 316d163a..85b91ad8 100644
--- a/Build/phpstan/Core12/phpstan.neon
+++ b/Build/phpstan/Core12/phpstan.neon
@@ -16,3 +16,7 @@ parameters:
     - ../../../.Build/*
     - ../../../Tests/Functional/Updates/Fixtures/Extension/test_extension/ext_emconf.php
     - ../../../Tests/Functional/Fixtures/Extensions/test_services_override/ext_emconf.php
+
+  typo3:
+    contextApiGetAspectMapping:
+      'frontend.preview': TYPO3\CMS\Frontend\Aspect\PreviewAspect
diff --git a/Classes/Event/Listener/RenderTranslatedFlagInFrontendPreviewMode.php b/Classes/Event/Listener/RenderTranslatedFlagInFrontendPreviewMode.php
new file mode 100644
index 00000000..eaffb0b0
--- /dev/null
+++ b/Classes/Event/Listener/RenderTranslatedFlagInFrontendPreviewMode.php
@@ -0,0 +1,77 @@
+<?php
+
+declare(strict_types=1);
+
+namespace WebVision\Deepltranslate\Core\Event\Listener;
+
+use TYPO3\CMS\Core\Context\Context;
+use TYPO3\CMS\Frontend\Controller\TypoScriptFrontendController;
+use TYPO3\CMS\Frontend\Event\AfterCacheableContentIsGeneratedEvent;
+use WebVision\Deepltranslate\Core\Hooks\DeeplPreviewFlagGeneratePageHook;
+
+/**
+ * Event listener to render the frontend preview flag information.
+ *
+ * TYPO3 v12+ only and this is the counter-part of the {@see DeeplPreviewFlagGeneratePageHook} for older TYPO3 versions.
+ * https://docs.typo3.org/c/typo3/cms-core/main/en-us/Changelog/12.0/Breaking-97862-HooksRelatedToGeneratingPageContentRemoved.html
+ */
+final class RenderTranslatedFlagInFrontendPreviewMode
+{
+    public function __invoke(AfterCacheableContentIsGeneratedEvent $event): void
+    {
+        $controller = $this->getTypoScriptFrontendController($event);
+        $context = $controller->getContext();
+        if (
+            !$this->isInPreviewMode($context)
+            || $this->processWorkspacePreview($context)
+            || ($controller->config['config']['disablePreviewNotification'] ?? false)
+            || (
+                isset($controller->page['tx_wvdeepltranslate_translated_time'])
+                && $controller->page['tx_wvdeepltranslate_translated_time'] === 0
+            )
+        ) {
+            // Preview flag must not be inserted. Return early.
+            return;
+        }
+
+        $messagePreviewLabel = ($controller->config['config']['deepl_message_preview'] ?? '')
+            ?: 'Translated with DeepL';
+
+        $styles = [];
+        $styles[] = 'position: fixed';
+        $styles[] = 'top: 65px';
+        $styles[] = 'right: 15px';
+        $styles[] = 'padding: 8px 18px';
+        $styles[] = 'background: #006494';
+        $styles[] = 'border: 1px solid #006494';
+        $styles[] = 'font-family: sans-serif';
+        $styles[] = 'font-size: 14px';
+        $styles[] = 'font-weight: bold';
+        $styles[] = 'color: #fff';
+        $styles[] = 'z-index: 20000';
+        $styles[] = 'user-select: none';
+        $styles[] = 'pointer-events: none';
+        $styles[] = 'text-align: center';
+        $styles[] = 'border-radius: 2px';
+        $message = '<div id="deepl-preview-info" style="' . implode(';', $styles) . '">' . htmlspecialchars($messagePreviewLabel) . '</div>';
+
+        $controller->content = str_ireplace('</body>', $message . '</body>', $controller->content);
+    }
+
+    private function isInPreviewMode(Context $context): bool
+    {
+        return $context->hasAspect('frontend.preview')
+            && $context->getPropertyFromAspect('frontend.preview', 'isPreview', false);
+    }
+
+    private function processWorkspacePreview(Context $context): bool
+    {
+        return $context->hasAspect('workspace')
+            && $context->getPropertyFromAspect('workspace', 'isOffline', false);
+    }
+
+    private function getTypoScriptFrontendController(AfterCacheableContentIsGeneratedEvent $event): TypoScriptFrontendController
+    {
+        return $event->getController();
+    }
+}
diff --git a/Configuration/Services.php b/Configuration/Services.php
index 84366ade..d122d354 100644
--- a/Configuration/Services.php
+++ b/Configuration/Services.php
@@ -19,6 +19,7 @@
 use WebVision\Deepltranslate\Core\Controller\Backend\AjaxController;
 use WebVision\Deepltranslate\Core\Controller\GlossarySyncController;
 use WebVision\Deepltranslate\Core\Event\Listener\GlossarySyncButtonProvider;
+use WebVision\Deepltranslate\Core\Event\Listener\RenderTranslatedFlagInFrontendPreviewMode;
 use WebVision\Deepltranslate\Core\Event\Listener\UsageToolBarEventListener;
 use WebVision\Deepltranslate\Core\Form\Item\SiteConfigSupportedLanguageItemsProcFunc;
 use WebVision\Deepltranslate\Core\Form\User\HasFormalitySupport;
@@ -161,6 +162,18 @@
             ]
         );
 
+    if ((new Typo3Version())->getMajorVersion() >= 12) {
+        // @todo Unnest this in next major when TYPO3 v11 support has been removed.
+        $services
+            ->set(RenderTranslatedFlagInFrontendPreviewMode::class)
+            ->tag(
+                'event.listener',
+                [
+                    'identifier' => 'deepltranslate-core/render-translated-flag-in-frontend-preview-mode',
+                ]
+            );
+    }
+
     /**
      * Check if WidgetRegistry is defined, which means that EXT:dashboard is available.
      * Registration directly in Services.yaml will break without EXT:dashboard installed!
diff --git a/ext_localconf.php b/ext_localconf.php
index 0ffb892b..76dff73f 100644
--- a/ext_localconf.php
+++ b/ext_localconf.php
@@ -3,6 +3,8 @@
 defined('TYPO3') or die();
 
 (static function (): void {
+    $typo3version = new \TYPO3\CMS\Core\Information\Typo3Version();
+
     //allowLanguageSynchronizationHook manipulates l10n_state
     $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['t3lib/class.t3lib_tcemain.php']['processDatamapClass'][]
         = \WebVision\Deepltranslate\Core\Hooks\AllowLanguageSynchronizationHook::class;
@@ -24,8 +26,11 @@
     $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['t3lib/class.t3lib_tcemain.php']['checkModifyAccessList']['deepl']
         = \WebVision\Deepltranslate\Core\Hooks\TCEmainHook::class;
 
-    $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['tslib/class.tslib_fe.php']['contentPostProc-all']['deepl-1675946132'] =
-        \WebVision\Deepltranslate\Core\Hooks\DeeplPreviewFlagGeneratePageHook::class . '->renderDeeplPreviewFlag';
+    if ($typo3version->getMajorVersion() < 12) {
+        // @todo Remove when TYPO3 v11 support is removed.
+        $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['tslib/class.tslib_fe.php']['contentPostProc-all']['deepl-1675946132'] =
+            \WebVision\WvDeepltranslate\Hooks\DeeplPreviewFlagGeneratePageHook::class . '->renderDeeplPreviewFlag';
+    }
 
     //xclass localizationcontroller for localizeRecords() and process() action
     $GLOBALS['TYPO3_CONF_VARS']['SYS']['Objects'][\TYPO3\CMS\Backend\Controller\Page\LocalizationController::class] = [