diff --git a/typo3/sysext/backend/Classes/Form/FormDataProvider/DatabaseRowInitializeNew.php b/typo3/sysext/backend/Classes/Form/FormDataProvider/DatabaseRowInitializeNew.php
index 4ce2c47e6a73c2332ad3f49d523884adaeeb69ed..80f3f4149893e767b9da3bb4055fe3788fcbbec6 100644
--- a/typo3/sysext/backend/Classes/Form/FormDataProvider/DatabaseRowInitializeNew.php
+++ b/typo3/sysext/backend/Classes/Form/FormDataProvider/DatabaseRowInitializeNew.php
@@ -49,6 +49,7 @@ class DatabaseRowInitializeNew implements FormDataProviderInterface
         $result = $this->setDefaultsFromDefaultValues($result);
         $result = $this->setDefaultsFromInlineRelations($result);
         $result = $this->setDefaultsFromInlineParentLanguage($result);
+        $result = $this->setDefaultsFromInlineParentUid($result);
         $result = $this->setPid($result);
 
         return $result;
@@ -223,6 +224,24 @@ class DatabaseRowInitializeNew implements FormDataProviderInterface
         return $result;
     }
 
+    /**
+     * Set the parent uid of inline relations created via ajax to the corresponding foreign field
+     *
+     * @param array $result Result array
+     * @return array
+     */
+    protected function setDefaultsFromInlineParentUid(array $result): array
+    {
+        $isInlineChild = $result['isInlineChild'] ?? false;
+        $parentField = $result['inlineParentConfig']['foreign_field'] ?? false;
+
+        if ($isInlineChild && $parentField && !empty($result['inlineParentUid'])) {
+            $result['databaseRow'][$parentField] = $result['inlineParentUid'];
+        }
+
+        return $result;
+    }
+
     /**
      * Set the pid. This is either the vanillaUid (see description in FormDataCompiler),
      * or a pid given by pageTsConfig for inline children.
diff --git a/typo3/sysext/backend/Tests/Unit/Form/FormDataProvider/DatabaseRowInitializeNewTest.php b/typo3/sysext/backend/Tests/Unit/Form/FormDataProvider/DatabaseRowInitializeNewTest.php
index 0fcb379a14507fcfc8d0c24d9994b4b8b8cefc08..3c47a36d37d2ce2b0ab2f35a0c11aac0508e26f6 100644
--- a/typo3/sysext/backend/Tests/Unit/Form/FormDataProvider/DatabaseRowInitializeNewTest.php
+++ b/typo3/sysext/backend/Tests/Unit/Form/FormDataProvider/DatabaseRowInitializeNewTest.php
@@ -709,4 +709,28 @@ class DatabaseRowInitializeNewTest extends UnitTestCase
         $expected['databaseRow']['pid'] = 42;
         self::assertSame($expected, (new DatabaseRowInitializeNew)->addData($input));
     }
+
+    /**
+     * @test
+     */
+    public function addDataSetsUidOfParentFieldIfRecordIsInlineChild()
+    {
+        $input = [
+            'command' => 'new',
+            'tableName' => 'aTable',
+            'vanillaUid' => 23,
+            'neighborRow' => null,
+            'inlineChildChildUid' => null,
+            'databaseRow' => [],
+            'isInlineChild' => true,
+            'inlineParentUid' => 42,
+            'inlineParentConfig' => [
+                'foreign_field' => 'theParentField'
+             ],
+        ];
+        $expected = $input;
+        $expected['databaseRow']['theParentField'] = 42;
+        $expected['databaseRow']['pid'] = 23;
+        self::assertSame($expected, (new DatabaseRowInitializeNew)->addData($input));
+    }
 }