diff --git a/pydantic2zod/_codegen.py b/pydantic2zod/_codegen.py
index bb51581..aca2d2a 100644
--- a/pydantic2zod/_codegen.py
+++ b/pydantic2zod/_codegen.py
@@ -33,9 +33,11 @@ def __init__(
         self,
         model_rename_rules: dict[str, str] | None = None,
         modify_models: Callable[[list[ClassDecl]], list[ClassDecl]] | None = None,
+        gen_header: Callable[[], str] | None = None,
     ) -> None:
         self._model_rename_rules = model_rename_rules or {}
         self._modify_models = modify_models or (lambda m: m)
+        self._gen_header = gen_header or (lambda: "")
 
     def to_zod(self, pydantic_models: list[ClassDecl]) -> str:
         self._apply_model_rename_rules(pydantic_models)
@@ -43,7 +45,7 @@ def to_zod(self, pydantic_models: list[ClassDecl]) -> str:
         _warn_about_duplicate_models(models)
 
         code = Lines()
-        self._gen_header(code)
+        code.add(self._gen_header())
 
         for cls in models:
             if not cls.name.startswith("_"):
@@ -52,16 +54,6 @@ def to_zod(self, pydantic_models: list[ClassDecl]) -> str:
 
         return str(code)
 
-    def _gen_header(self, code: "Lines") -> None:
-        header = """
-/**
- * NOTE: automatically generated by the pydantic2zod compiler.
- */
-
-import { z } from "zod";
-"""
-        code.add(header)
-
     def _apply_model_rename_rules(self, pydantic_models: list[ClassDecl]) -> None:
         for model in pydantic_models:
             if new_name := self._model_rename_rules.get(model.full_path):
diff --git a/pydantic2zod/_compiler.py b/pydantic2zod/_compiler.py
index 86fd465..c9a188b 100644
--- a/pydantic2zod/_compiler.py
+++ b/pydantic2zod/_compiler.py
@@ -33,7 +33,9 @@ class Compiler:
     """
 
     def __init__(self) -> None:
-        self._codegen = Codegen(self.MODEL_RENAME_RULES, self._modify_models)
+        self._codegen = Codegen(
+            self.MODEL_RENAME_RULES, self._modify_models, self._gen_header
+        )
         self._pydantic_models: list[ClassDecl] = []
 
     def parse(self, module_name: str) -> Self:
@@ -52,3 +54,13 @@ def _modify_models(self, pydantic_models: list[ClassDecl]) -> list[ClassDecl]:
         e.g. remove default field values.
         """
         return pydantic_models
+
+    def _gen_header(self) -> str:
+        """Override in case you want to add some header to the generated code."""
+        return """
+/**
+ * NOTE: automatically generated by the pydantic2zod compiler.
+ */
+
+import { z } from "zod";
+"""