diff --git a/src/Lexer.php b/src/Lexer.php
index 2e8f811223c..f58a0b02a4f 100644
--- a/src/Lexer.php
+++ b/src/Lexer.php
@@ -428,12 +428,7 @@ private function stripcslashes(string $str, string $quoteType): string
 
             if (isset(self::SPECIAL_CHARS[$nextChar])) {
                 $result .= self::SPECIAL_CHARS[$nextChar];
-            } elseif ($nextChar === '\\') {
-                $result .= $nextChar;
-            } elseif ($nextChar === "'" || $nextChar === '"') {
-                if ($nextChar !== $quoteType) {
-                    trigger_deprecation('twig/twig', '3.12', 'Character "%s" at position %d does not need to be escaped anymore.', $nextChar, $i + 1);
-                }
+            } elseif ($nextChar === '\\' || $nextChar === $quoteType) {
                 $result .= $nextChar;
             } elseif ($nextChar === '#' && $i + 1 < $length && $str[$i + 1] === '{') {
                 $result .= '#{';
@@ -451,8 +446,7 @@ private function stripcslashes(string $str, string $quoteType): string
                 }
                 $result .= chr(octdec($octal));
             } else {
-                trigger_deprecation('twig/twig', '3.12', sprintf('Character "%s" at position %d does not need to be escaped anymore.', $nextChar, $i + 1));
-                $result .= $nextChar;
+                $result .= '\\' . $nextChar;
             }
 
             $i++;
diff --git a/tests/LexerTest.php b/tests/LexerTest.php
index 81690829a08..2865021f3c7 100644
--- a/tests/LexerTest.php
+++ b/tests/LexerTest.php
@@ -12,7 +12,6 @@
  */
 
 use PHPUnit\Framework\TestCase;
-use Symfony\Bridge\PhpUnit\ExpectDeprecationTrait;
 use Twig\Environment;
 use Twig\Error\SyntaxError;
 use Twig\Lexer;
@@ -22,8 +21,6 @@
 
 class LexerTest extends TestCase
 {
-    use ExpectDeprecationTrait;
-
     public function testNameLabelForTag()
     {
         $template = '{% § %}';
@@ -195,6 +192,18 @@ public function testStringWithEscapedDelimiter(string $template, string $expecte
 
     public function getStringWithEscapedDelimiter()
     {
+        yield '{{ \'App\Test\' }} => App\Test' => [
+            '{{ \'App\\Test\' }}',
+            'App\Test',
+        ];
+        yield '{{ "foo \\\' bar" }} => foo \' bar' => [
+            '{{ "foo \\\' bar" }}',
+            "foo \' bar",
+        ];
+        yield '{{ \'foo \" bar\' }} => foo \" bar' => [
+            '{{ \'foo \\" bar\' }}',
+            'foo \" bar',
+        ];
         yield '{{ \'\x6\' }} => \x6' => [
             '{{ \'\x6\' }}',
             "\x6",
@@ -229,43 +238,6 @@ public function getStringWithEscapedDelimiter()
         ];
     }
 
-    /**
-     * @group legacy
-     * @dataProvider getStringWithEscapedDelimiterProducingDeprecation
-     */
-    public function testStringWithEscapedDelimiterProducingDeprecation(string $template, string $expected, string $expectedDeprecation)
-    {
-        $this->expectDeprecation($expectedDeprecation);
-
-        $lexer = new Lexer(new Environment(new ArrayLoader()));
-        $stream = $lexer->tokenize(new Source($template, 'index'));
-        $stream->expect(Token::VAR_START_TYPE);
-        $stream->expect(Token::STRING_TYPE, $expected);
-
-        // add a dummy assertion here to satisfy PHPUnit, the only thing we want to test is that the code above
-        // can be executed without throwing any exceptions
-        $this->addToAssertionCount(1);
-    }
-
-    public function getStringWithEscapedDelimiterProducingDeprecation()
-    {
-        yield '{{ \'App\Test\' }} => AppTest' => [
-            '{{ \'App\\Test\' }}',
-            'AppTest',
-            "Since twig/twig 3.12: Character \"T\" at position 5 does not need to be escaped anymore.",
-        ];
-        yield '{{ "foo \\\' bar" }} => foo \' bar' => [
-            '{{ "foo \\\' bar" }}',
-            'foo \' bar',
-            "Since twig/twig 3.12: Character \"'\" at position 6 does not need to be escaped anymore.",
-        ];
-        yield '{{ \'foo \" bar\' }} => foo " bar' => [
-            '{{ \'foo \\" bar\' }}',
-            'foo " bar',
-            'Since twig/twig 3.12: Character """ at position 6 does not need to be escaped anymore.',
-        ];
-    }
-
     public function testStringWithInterpolation()
     {
         $template = 'foo {{ "bar #{ baz + 1 }" }}';