diff --git a/src/dbus_fast/_private/marshaller.py b/src/dbus_fast/_private/marshaller.py
index 777fe1c..2e7e3e2 100644
--- a/src/dbus_fast/_private/marshaller.py
+++ b/src/dbus_fast/_private/marshaller.py
@@ -20,8 +20,9 @@ class Marshaller:
         return offset
 
     def write_boolean(self, boolean: bool, _=None) -> int:
+        written = self.align(4)
         self.buffer.extend(PACK_UINT32(int(boolean)))
-        return self.align(4) + 4
+        return written + 4
 
     def write_signature(self, signature: str, _=None) -> int:
         signature = signature.encode()
diff --git a/tests/data/messages.json b/tests/data/messages.json
index fcce840..a979847 100644
--- a/tests/data/messages.json
+++ b/tests/data/messages.json
@@ -230,5 +230,17 @@
       ]
     },
     "data": "6c01000120000000010000007900000001016f00150000002f6f72672f667265656465736b746f702f4442757300000002017300140000006f72672e667265656465736b746f702e4442757300000000030173000500000048656c6c6f00000006017300140000006f72672e667265656465736b746f702e444275730000000008016700037661730000000000000000017600017300000005000000776f726c64000000080000000300000062617200"
+  },
+  {
+    "message": {
+      "destination": "org.freedesktop.DBus",
+      "path": "/org/freedesktop/DBus",
+      "interface": "org.freedesktop.DBus",
+      "member": "Hello",
+      "serial": 1,
+      "signature": "asbbasbb",
+      "body": [["hello", "worl"], true, false, ["hello", "worl"], true, false]
+    },
+    "data": "6c01000148000000010000007e00000001016f00150000002f6f72672f667265656465736b746f702f4442757300000002017300140000006f72672e667265656465736b746f702e4442757300000000030173000500000048656c6c6f00000006017300140000006f72672e667265656465736b746f702e444275730000000008016700086173626261736262000000150000000500000068656c6c6f00000004000000776f726c000000000100000000000000150000000500000068656c6c6f00000004000000776f726c000000000100000000000000"
   }
 ]