diff --git a/addons/sale_timesheet/models/account.py b/addons/sale_timesheet/models/account.py
index c535335a337..3e3444f3567 100644
--- a/addons/sale_timesheet/models/account.py
+++ b/addons/sale_timesheet/models/account.py
@@ -37,7 +37,7 @@ class AccountAnalyticLine(models.Model):
             ('is_service', '=', True),
             ('is_expense', '=', False),
             ('state', '=', 'sale'),
-            ('order_partner_id', 'child_of', self.commercial_partner_id.ids)
+            ('order_partner_id', 'child_of', self.sudo().commercial_partner_id.ids)
         ], super()._default_sale_line_domain()])
 
     @api.depends('commercial_partner_id')
diff --git a/addons/sale_timesheet/tests/__init__.py b/addons/sale_timesheet/tests/__init__.py
index 3136159e53c..21e63afa4ba 100644
--- a/addons/sale_timesheet/tests/__init__.py
+++ b/addons/sale_timesheet/tests/__init__.py
@@ -12,6 +12,7 @@ from . import test_project_billing_multicompany
 from . import test_upsell_warning
 from . import test_edit_so_line_timesheet
 from . import test_so_line_determined_in_timesheet
+from . import test_sale_timesheet_portal
 from . import test_sale_timesheet_ui
 from . import test_project_pricing_type
 from . import test_project_update
diff --git a/addons/sale_timesheet/tests/test_sale_timesheet_portal.py b/addons/sale_timesheet/tests/test_sale_timesheet_portal.py
new file mode 100644
index 00000000000..9051839fffa
--- /dev/null
+++ b/addons/sale_timesheet/tests/test_sale_timesheet_portal.py
@@ -0,0 +1,38 @@
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
+from odoo import Command
+from odoo.tests import tagged
+
+from odoo.addons.project.tests.test_project_sharing import TestProjectSharingCommon
+from odoo.addons.sale_timesheet.tests.common import TestCommonSaleTimesheet
+
+@tagged('post_install', '-at_install')
+class TestSaleTimesheetPortal(TestProjectSharingCommon, TestCommonSaleTimesheet):
+
+    def test_ensure_allowed_so_line_field_access(self):
+        """ Ensure that the field so_line of account.analytic.line is accessible for portal user"""
+        # A portal collaborator is added to a project to enable the rule analytic.account.analytic.line.timesheet.portal.user
+        self.project_task_rate.write({
+            'collaborator_ids': [
+                Command.create({'partner_id': self.user_portal.partner_id.id}),
+            ],
+            'privacy_visibility': 'portal',
+            'message_partner_ids': [
+                Command.link(self.user_portal.partner_id.id),
+            ],
+        })
+        task1 = self.env['project.task'].create({
+            'name': 'Test Task',
+            'project_id': self.project_task_rate.id,
+        })
+        # log some timesheets (on the project accessible in portal)
+        timesheet1 = self.env['account.analytic.line'].create({
+            'name': 'Test Line',
+            'project_id': self.project_task_rate.id,
+            'task_id': task1.id,
+            'unit_amount': 10.5,
+            'employee_id': self.employee_user.id,
+        })
+        # Accessing field allowed_so_line_ids as a portal user should not raise any access error
+        self.env.invalidate_all()
+        timesheet1.with_user(self.user_portal).read(['allowed_so_line_ids'])