diff --git a/report_py3o/models/ir_actions_report.py b/report_py3o/models/ir_actions_report.py
index ccb067e9a4..500247b138 100644
--- a/report_py3o/models/ir_actions_report.py
+++ b/report_py3o/models/ir_actions_report.py
@@ -2,6 +2,8 @@
 # Copyright 2018 ACSONE SA/NV
 # License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
 import logging
+from collections import OrderedDict
+from io import BytesIO
 
 from odoo import _, api, fields, models
 from odoo.exceptions import ValidationError
@@ -171,6 +173,36 @@ def _render_py3o(self, report_ref, res_ids, data=None):
             .create_report(res_ids, data)
         )
 
+    def _pre_render_qweb_pdf(self, report_ref, res_ids=None, data=None):
+        report = self._get_report(report_ref)
+        if report.report_type != "py3o":
+            return super()._pre_render_qweb_pdf(
+                report_ref,
+                res_ids=res_ids,
+                data=data,
+            )
+
+        if isinstance(res_ids, int):
+            res_ids = [res_ids]
+
+        collected_streams = OrderedDict()
+        for res_id in res_ids or []:
+            content, report_type = self._render(report_ref, [res_id], data=data)
+            if report_type != "pdf":
+                raise ValidationError(
+                    _(
+                        "Py3O report '%(report)s' must generate PDF output for "
+                        "invoice sending. Current output format: %(format)s"
+                    )
+                    % {"report": report.display_name, "format": report_type}
+                )
+            collected_streams[res_id] = {
+                "stream": BytesIO(content),
+                "attachment": None,
+            }
+
+        return collected_streams, "pdf"
+
     def gen_report_download_filename(self, res_ids, data):
         """Override this function to change the name of the downloaded report"""
         self.ensure_one()
diff --git a/report_py3o/tests/test_report_py3o.py b/report_py3o/tests/test_report_py3o.py
index 713fb25935..043500f58f 100644
--- a/report_py3o/tests/test_report_py3o.py
+++ b/report_py3o/tests/test_report_py3o.py
@@ -266,3 +266,34 @@ def test_py3o_report_availability(self):
         self.assertFalse(self.report.msg_py3o_report_not_available)
         res = self.report._render(self.report.id, self.env.user.ids)
         self.assertTrue(res)
+
+    def test_pre_render_qweb_pdf_py3o_streams(self):
+        with mock.patch.object(
+            self.report.__class__,
+            "_render",
+            return_value=(b"pdf-content", "pdf"),
+        ) as mocked_render:
+            streams, report_type = self.report._pre_render_qweb_pdf(
+                self.report.report_name,
+                res_ids=self.env.user.ids,
+            )
+
+        self.assertEqual(report_type, "pdf")
+        self.assertEqual(set(streams.keys()), set(self.env.user.ids))
+        for stream_data in streams.values():
+            self.assertEqual(stream_data["stream"].getvalue(), b"pdf-content")
+            stream_data["stream"].close()
+
+        self.assertEqual(mocked_render.call_count, len(self.env.user.ids))
+
+    def test_pre_render_qweb_pdf_py3o_non_pdf(self):
+        with mock.patch.object(
+            self.report.__class__,
+            "_render",
+            return_value=(b"odt-content", "odt"),
+        ):
+            with self.assertRaises(ValidationError):
+                self.report._pre_render_qweb_pdf(
+                    self.report.report_name,
+                    res_ids=[self.env.user.id],
+                )