diff --git a/doc/api/resources/invoices.rst b/doc/api/resources/invoices.rst
index 68e166d02..ac69feb3a 100644
--- a/doc/api/resources/invoices.rst
+++ b/doc/api/resources/invoices.rst
@@ -58,6 +58,12 @@ lines                                 list of objects            The actual invo
                                                                  created before this field was introduced as well as for
                                                                  all lines not created by a product (e.g. a shipping or
                                                                  cancellation fee).
+├ subevent                            integer                    Event series date ID used to create this line. Note that everything
+                                                                 about the subevent might have changed since the creation
+                                                                 of the invoice. Can be ``null`` for all invoice lines
+                                                                 created before this field was introduced as well as for
+                                                                 all lines not created by a product (e.g. a shipping or
+                                                                 cancellation fee) as well as for all events that are not a series.
 ├ fee_type                            string                     Fee type, e.g. ``shipping``, ``service``, ``payment``,
                                                                  ``cancellation``, ``giftcard``, or ``other. Can be ``null`` for
                                                                  all invoice lines
@@ -120,6 +126,10 @@ internal_reference                    string                     Customer's refe
 
    The attribute ``lines.event_location`` has been added.
 
+.. versionchanged:: 4.6
+
+   The attribute ``lines.subevent`` has been added.
+
 
 Endpoints
 ---------
@@ -185,6 +195,7 @@ Endpoints
                 "description": "Budget Ticket",
                 "item": 1234,
                 "variation": 245,
+                "subevent": null,
                 "fee_type": null,
                 "fee_internal_type": null,
                 "event_date_from": "2017-12-27T10:00:00Z",
@@ -274,6 +285,7 @@ Endpoints
             "description": "Budget Ticket",
             "item": 1234,
             "variation": 245,
+            "subevent": null,
             "fee_type": null,
             "fee_internal_type": null,
             "event_date_from": "2017-12-27T10:00:00Z",
diff --git a/src/pretix/api/serializers/order.py b/src/pretix/api/serializers/order.py
index 17a14eb64..78991180c 100644
--- a/src/pretix/api/serializers/order.py
+++ b/src/pretix/api/serializers/order.py
@@ -1426,7 +1426,7 @@ class InlineInvoiceLineSerializer(I18nAwareModelSerializer):
 
     class Meta:
         model = InvoiceLine
-        fields = ('position', 'description', 'item', 'variation', 'attendee_name', 'event_date_from',
+        fields = ('position', 'description', 'item', 'variation', 'subevent', 'attendee_name', 'event_date_from',
                   'event_date_to', 'gross_value', 'tax_value', 'tax_rate', 'tax_name', 'fee_type',
                   'fee_internal_type', 'event_location')
 
diff --git a/src/tests/api/test_orders.py b/src/tests/api/test_orders.py
index ad690604a..129ff7142 100644
--- a/src/tests/api/test_orders.py
+++ b/src/tests/api/test_orders.py
@@ -1020,6 +1020,7 @@ TEST_INVOICE_RES = {
         {
             "position": 1,
             "description": "Budget Ticket<br />Attendee: Peter",
+            'subevent': None,
             'event_date_from': '2017-12-27T10:00:00Z',
             'event_date_to': None,
             'event_location': None,
@@ -1036,6 +1037,7 @@ TEST_INVOICE_RES = {
         {
             "position": 2,
             "description": "Payment fee",
+            'subevent': None,
             'event_date_from': '2017-12-27T10:00:00Z',
             'event_date_to': None,
             'event_location': None,
@@ -4440,6 +4442,7 @@ def test_order_create_invoice(token_client, organizer, event, order):
             {
                 'position': 1,
                 'description': 'Budget Ticket<br />Attendee: Peter',
+                'subevent': None,
                 'event_date_from': '2017-12-27T10:00:00Z',
                 'event_date_to': None,
                 'event_location': None,
@@ -4456,6 +4459,7 @@ def test_order_create_invoice(token_client, organizer, event, order):
             {
                 'position': 2,
                 'description': 'Payment fee',
+                'subevent': None,
                 'event_date_from': '2017-12-27T10:00:00Z',
                 'event_date_to': None,
                 'event_location': None,