diff --git a/src/Checker/TypeChecker.php b/src/Checker/TypeChecker.php
index 4dbea5b..4aadfbe 100644
--- a/src/Checker/TypeChecker.php
+++ b/src/Checker/TypeChecker.php
@@ -33,8 +33,12 @@ public function notNull(mixed $value): bool
     /**
      * Value has to be boolean or integer[0,1].
      */
-    public function boolean(mixed $value): bool
+    public function boolean(mixed $value, bool $strict = false): bool
     {
-        return \is_bool($value) || (\is_numeric($value) && ($value === 0 || $value === 1));
+        if (\is_bool($value)) {
+            return true;
+        }
+
+        return  false === $strict && (\is_numeric($value) && ($value === 0 || $value === 1));
     }
 }
diff --git a/tests/src/Unit/Checkers/TypesTest.php b/tests/src/Unit/Checkers/TypesTest.php
index 0e97c93..8e8f094 100644
--- a/tests/src/Unit/Checkers/TypesTest.php
+++ b/tests/src/Unit/Checkers/TypesTest.php
@@ -66,4 +66,19 @@ public function testBoolean(): void
         $this->assertFalse($checker->boolean('0'));
         $this->assertFalse($checker->boolean('1'));
     }
+
+    public function testBooleanStrict(): void
+    {
+        $checker = new TypeChecker();
+
+        $this->assertTrue($checker->boolean(true, true));
+        $this->assertTrue($checker->boolean(false, true));
+
+        $this->assertFalse($checker->boolean(1, true));
+        $this->assertFalse($checker->boolean(0, true));
+        $this->assertFalse($checker->boolean('true', true));
+        $this->assertFalse($checker->boolean('false', true));
+        $this->assertFalse($checker->boolean('0', true));
+        $this->assertFalse($checker->boolean('1', true));
+    }
 }