diff --git a/django/db/models/sql/query.py b/django/db/models/sql/query.py
index f96a0a6e2d..78c4f47b5b 100644
--- a/django/db/models/sql/query.py
+++ b/django/db/models/sql/query.py
@@ -2093,13 +2093,6 @@ class Query(BaseExpression):
         self.clear_deferred_loading()
         self.clear_select_fields()
 
-        if self.group_by is True:
-            self.add_fields((f.attname for f in self.model._meta.concrete_fields), False)
-            # Disable GROUP BY aliases to avoid orphaning references to the
-            # SELECT clause which is about to be cleared.
-            self.set_group_by(allow_aliases=False)
-            self.clear_select_fields()
-
         if fields:
             field_names = []
             extra_names = []
@@ -2121,6 +2114,14 @@ class Query(BaseExpression):
             self.set_annotation_mask(annotation_names)
         else:
             field_names = [f.attname for f in self.model._meta.concrete_fields]
+        # Selected annotations must be known before setting the GROUP BY
+        # clause.
+        if self.group_by is True:
+            self.add_fields((f.attname for f in self.model._meta.concrete_fields), False)
+            # Disable GROUP BY aliases to avoid orphaning references to the
+            # SELECT clause which is about to be cleared.
+            self.set_group_by(allow_aliases=False)
+            self.clear_select_fields()
 
         self.values_select = tuple(field_names)
         self.add_fields(field_names, True)
diff --git a/tests/aggregation/tests.py b/tests/aggregation/tests.py
index f523b3ca35..06c4cc7ccb 100644
--- a/tests/aggregation/tests.py
+++ b/tests/aggregation/tests.py
@@ -1165,6 +1165,31 @@ class AggregateTestCase(TestCase):
             'Sams',
         ])
 
+    def test_aggregation_subquery_annotation_values(self):
+        """
+        Subquery annotations and external aliases are excluded from the GROUP
+        BY if they are not selected.
+        """
+        books_qs = Book.objects.annotate(
+            first_author_the_same_age=Subquery(
+                Author.objects.filter(
+                    age=OuterRef('contact__friends__age'),
+                ).order_by('age').values('id')[:1],
+            )
+        ).filter(
+            publisher=self.p1,
+            first_author_the_same_age__isnull=False,
+        ).annotate(
+            min_age=Min('contact__friends__age'),
+        ).values('name', 'min_age').order_by('name')
+        self.assertEqual(list(books_qs), [
+            {'name': 'Practical Django Projects', 'min_age': 34},
+            {
+                'name': 'The Definitive Guide to Django: Web Development Done Right',
+                'min_age': 29,
+            },
+        ])
+
     @skipUnlessDBFeature('supports_subqueries_in_group_by')
     def test_group_by_subquery_annotation(self):
         """