diff --git a/src/gui/editorwidgets/qgsrelationreferencewidget.cpp b/src/gui/editorwidgets/qgsrelationreferencewidget.cpp
index 07d93fbfb1c..0bd4ad53981 100644
--- a/src/gui/editorwidgets/qgsrelationreferencewidget.cpp
+++ b/src/gui/editorwidgets/qgsrelationreferencewidget.cpp
@@ -208,7 +208,6 @@ void QgsRelationReferenceWidget::setRelation( const QgsRelation &relation, bool
       mComboBox->setIdentifierField( mReferencedField );
 
     mReferencedFieldIdx = mReferencedLayer->fields().lookupField( relation.fieldPairs().at( 0 ).second );
-    mReferencingFieldIdx = mReferencingLayer->fields().lookupField( relation.fieldPairs().at( 0 ).first );
     mAttributeEditorFrame->setObjectName( QStringLiteral( "referencing/" ) + relation.name() );
 
 
@@ -897,7 +896,7 @@ void QgsRelationReferenceWidget::addEntry()
 
   if ( mEditorContext.vectorLayerTools()->addFeature( mReferencedLayer, attributes, QgsGeometry(), &f ) )
   {
-    mComboBox->setIdentifierValue( f.attribute( mReferencingFieldIdx ) );
+    mComboBox->setIdentifierValue( f.attribute( mReferencedFieldIdx ) );
     mAddEntryButton->setEnabled( false );
   }
 }
diff --git a/tests/src/gui/testqgsrelationreferencewidget.cpp b/tests/src/gui/testqgsrelationreferencewidget.cpp
index d47cd3ecb9c..6f8e7057a29 100644
--- a/tests/src/gui/testqgsrelationreferencewidget.cpp
+++ b/tests/src/gui/testqgsrelationreferencewidget.cpp
@@ -29,6 +29,7 @@
 #include "qgsfeaturefiltermodel.h"
 #include "qgsgui.h"
 #include "qgsmapcanvas.h"
+#include "qgsvectorlayertools.h"
 
 class TestQgsRelationReferenceWidget : public QObject
 {
@@ -48,6 +49,7 @@ class TestQgsRelationReferenceWidget : public QObject
     void testInvalidRelation();
     void testSetGetForeignKey();
     void testIdentifyOnMap();
+    void testAddEntry();
 
   private:
     std::unique_ptr<QgsVectorLayer> mLayer1;
@@ -374,5 +376,48 @@ void TestQgsRelationReferenceWidget::testIdentifyOnMap()
   mLayer1->rollBack();
 }
 
+
+void TestQgsRelationReferenceWidget::testAddEntry()
+{
+  // check that a new added entry in referenced layer populate correctly the
+  // referencing combobox
+  QWidget parentWidget;
+  QgsRelationReferenceWidget w( &parentWidget );
+  QVERIFY( mLayer1->startEditing() );
+  w.setRelation( *mRelation, true );
+  w.init();
+
+  // Monkey patch gui vector layer tool in order to simple add a new feature in
+  // referenced layer
+  class DummyVectorLayerTools : public QgsVectorLayerTools
+  {
+      bool addFeature( QgsVectorLayer *layer, const QgsAttributeMap &, const QgsGeometry &, QgsFeature *feat = nullptr ) const override
+      {
+        feat->setAttribute( QStringLiteral( "pk" ), 13 );
+        feat->setAttribute( QStringLiteral( "material" ), "steel" );
+        feat->setAttribute( QStringLiteral( "diameter" ), 140 );
+        feat->setAttribute( QStringLiteral( "raccord" ), "collar" );
+        layer->addFeature( *feat );
+        return true;
+      }
+
+      bool startEditing( QgsVectorLayer * ) const override {return true;}
+
+      bool stopEditing( QgsVectorLayer *, bool = true ) const override {return true;};
+
+      bool saveEdits( QgsVectorLayer * ) const override {return true;};
+  };
+
+  QgsAttributeEditorContext context;
+  DummyVectorLayerTools tools;
+  context.setVectorLayerTools( &tools );
+  w.setEditorContext( context, nullptr, nullptr );
+  w.addEntry();
+
+  QCOMPARE( w.mComboBox->identifierValue(), 13 );
+}
+
+
+
 QGSTEST_MAIN( TestQgsRelationReferenceWidget )
 #include "testqgsrelationreferencewidget.moc"