diff --git a/python/core/auto_generated/qgsfieldmodel.sip.in b/python/core/auto_generated/qgsfieldmodel.sip.in
index 497ae7bdeb4..256b7882d03 100644
--- a/python/core/auto_generated/qgsfieldmodel.sip.in
+++ b/python/core/auto_generated/qgsfieldmodel.sip.in
@@ -128,12 +128,20 @@ Returns the layer associated with the model.
     virtual QVariant data( const QModelIndex &index, int role ) const;
 
 
-    static QString fieldToolTip( const QgsField &field, const QString &expression = QString() );
+    static QString fieldToolTip( const QgsField &field );
 %Docstring
 Returns a HTML formatted tooltip string for a ``field``, containing details
 like the field name, alias and type.
 
 .. versionadded:: 3.0
+%End
+
+    static QString fieldToolTipExtended( const QgsField &field, const QgsVectorLayer *layer );
+%Docstring
+Returns a HTML formatted tooltip string for a ``field``, containing details
+like the field name, alias, type and expression.
+
+.. versionadded:: 3.14
 %End
 
     void setFields( const QgsFields &fields );
diff --git a/src/app/qgsidentifyresultsdialog.cpp b/src/app/qgsidentifyresultsdialog.cpp
index 51266aef415..0a9aece3d02 100644
--- a/src/app/qgsidentifyresultsdialog.cpp
+++ b/src/app/qgsidentifyresultsdialog.cpp
@@ -626,11 +626,8 @@ void QgsIdentifyResultsDialog::addFeature( QgsVectorLayer *vlayer, const QgsFeat
     QgsTreeWidgetItem *attrItem = new QgsTreeWidgetItem( QStringList() << QString::number( i ) << value );
     featItem->addChild( attrItem );
 
-    QString expressionString = fields.fieldOrigin( i ) == QgsFields::OriginExpression
-                               ? vlayer->expressionField( i )
-                               : QString();
     attrItem->setData( 0, Qt::DisplayRole, vlayer->attributeDisplayName( i ) );
-    attrItem->setToolTip( 0, QgsFieldModel::fieldToolTip( fields.at( i ), expressionString ) );
+    attrItem->setToolTip( 0, QgsFieldModel::fieldToolTipExtended( fields.at( i ), vlayer ) );
     attrItem->setData( 0, Qt::UserRole, fields.at( i ).name() );
     attrItem->setData( 0, Qt::UserRole + 1, i );
 
diff --git a/src/core/qgsfieldmodel.cpp b/src/core/qgsfieldmodel.cpp
index fb5e9de4506..37d423600eb 100644
--- a/src/core/qgsfieldmodel.cpp
+++ b/src/core/qgsfieldmodel.cpp
@@ -464,7 +464,7 @@ QVariant QgsFieldModel::data( const QModelIndex &index, int role ) const
   }
 }
 
-QString QgsFieldModel::fieldToolTip( const QgsField &field, const QString &expression )
+QString QgsFieldModel::fieldToolTip( const QgsField &field )
 {
   QString toolTip;
   if ( !field.alias().isEmpty() )
@@ -485,9 +485,25 @@ QString QgsFieldModel::fieldToolTip( const QgsField &field, const QString &expre
     toolTip += QStringLiteral( "<br><em>%1</em>" ).arg( comment );
   }
 
-  if ( ! expression.isEmpty() )
+  return toolTip;
+}
+
+QString QgsFieldModel::fieldToolTipExtended( const QgsField &field, const QgsVectorLayer *layer )
+{
+  QString toolTip = QgsFieldModel::fieldToolTip( field );
+  const QgsFields fields = layer->fields();
+  int fieldIdx = fields.indexOf( field.name() );
+
+  if ( fieldIdx < 0 )
+    return QString();
+
+  QString expressionString = fields.fieldOrigin( fieldIdx ) == QgsFields::OriginExpression
+                             ? layer->expressionField( fieldIdx )
+                             : QString();
+
+  if ( !expressionString.isEmpty() )
   {
-    toolTip += QStringLiteral( "<br><font style='font-family:monospace;'>%3</font>" ).arg( expression );
+    toolTip += QStringLiteral( "<br><font style='font-family:monospace;'>%3</font>" ).arg( expressionString );
   }
 
   return toolTip;
diff --git a/src/core/qgsfieldmodel.h b/src/core/qgsfieldmodel.h
index 34e702b71b4..cab1bea0b14 100644
--- a/src/core/qgsfieldmodel.h
+++ b/src/core/qgsfieldmodel.h
@@ -135,7 +135,14 @@ class CORE_EXPORT QgsFieldModel : public QAbstractItemModel
      * like the field name, alias and type.
      * \since QGIS 3.0
      */
-    static QString fieldToolTip( const QgsField &field, const QString &expression = QString() );
+    static QString fieldToolTip( const QgsField &field );
+
+    /**
+     * Returns a HTML formatted tooltip string for a \a field, containing details
+     * like the field name, alias, type and expression.
+     * \since QGIS 3.14
+     */
+    static QString fieldToolTipExtended( const QgsField &field, const QgsVectorLayer *layer );
 
     /**
      * Manually sets the \a fields to use for the model.
diff --git a/src/gui/attributetable/qgsattributetablemodel.cpp b/src/gui/attributetable/qgsattributetablemodel.cpp
index 409e5e950a7..13413b8c434 100644
--- a/src/gui/attributetable/qgsattributetablemodel.cpp
+++ b/src/gui/attributetable/qgsattributetablemodel.cpp
@@ -624,10 +624,7 @@ QVariant QgsAttributeTableModel::headerData( int section, Qt::Orientation orient
     else
     {
       const QgsField field = layer()->fields().at( mAttributes.at( section ) );
-      QString expressionString = layer()->fields().fieldOrigin( mAttributes.at( section ) ) == QgsFields::OriginExpression
-                                 ? layer()->expressionField( mAttributes.at( section ) )
-                                 : QString();
-      return QgsFieldModel::fieldToolTip( field, expressionString );
+      return QgsFieldModel::fieldToolTipExtended( field, layer() );
     }
   }
   else
diff --git a/src/gui/qgsattributeform.cpp b/src/gui/qgsattributeform.cpp
index ddc3f3fdde0..79a9826ce4c 100644
--- a/src/gui/qgsattributeform.cpp
+++ b/src/gui/qgsattributeform.cpp
@@ -1506,11 +1506,8 @@ void QgsAttributeForm::init()
       bool labelOnTop = mLayer->editFormConfig().labelOnTop( idx );
 
       // This will also create the widget
-      QString expressionString = fields.fieldOrigin( idx ) == QgsFields::OriginExpression
-                                 ? mLayer->expressionField( idx )
-                                 : QString();
       QLabel *l = new QLabel( labelText );
-      l->setToolTip( QgsFieldModel::fieldToolTip( field, expressionString ) );
+      l->setToolTip( QgsFieldModel::fieldToolTipExtended( field, mLayer ) );
       QSvgWidget *i = new QSvgWidget();
       i->setFixedSize( 18, 18 );
 
diff --git a/tests/src/python/test_qgsfieldmodel.py b/tests/src/python/test_qgsfieldmodel.py
index 703c4468452..2c976d48e41 100644
--- a/tests/src/python/test_qgsfieldmodel.py
+++ b/tests/src/python/test_qgsfieldmodel.py
@@ -360,12 +360,19 @@ class TestQgsFieldModel(unittest.TestCase):
         self.assertEqual(QgsFieldModel.fieldToolTip(f), "<b>my_real</b><br><font style='font-family:monospace; white-space: nowrap;'>real(8, 3) NULL</font>")
         f.setComment('Comment text')
         self.assertEqual(QgsFieldModel.fieldToolTip(f), "<b>my_real</b><br><font style='font-family:monospace; white-space: nowrap;'>real(8, 3) NULL</font><br><em>Comment text</em>")
-        self.assertEqual(QgsFieldModel.fieldToolTip(f, '1+1'), "<b>my_real</b><br><font style='font-family:monospace; white-space: nowrap;'>real(8, 3) NULL</font><br><em>Comment text</em><br><font style='font-family:monospace;'>1+1</font>")
+
+    def testFieldTooltipExtended(self):
+        layer = QgsVectorLayer("Point?", "tooltip", "memory")
+        f = QgsField('my_real', QVariant.Double, 'real', 8, 3, 'Comment text')
+        layer.addExpressionField('1+1', f)
+        layer.updateFields()
+        self.assertEqual(QgsFieldModel.fieldToolTipExtended(QgsField('my_string', QVariant.String, 'string'), layer), '')
+        self.assertEqual(QgsFieldModel.fieldToolTipExtended(f, layer), "<b>my_real</b><br><font style='font-family:monospace; white-space: nowrap;'>real(8, 3) NULL</font><br><em>Comment text</em><br><font style='font-family:monospace;'>1+1</font>")
         f.setAlias('my alias')
         constraints = f.constraints()
         constraints.setConstraint(QgsFieldConstraints.ConstraintUnique)
         f.setConstraints(constraints)
-        self.assertEqual(QgsFieldModel.fieldToolTip(f, '1+1'), "<b>my alias</b> (my_real)<br><font style='font-family:monospace; white-space: nowrap;'>real(8, 3) NULL UNIQUE</font><br><em>Comment text</em><br><font style='font-family:monospace;'>1+1</font>")
+        self.assertEqual(QgsFieldModel.fieldToolTipExtended(f, layer), "<b>my alias</b> (my_real)<br><font style='font-family:monospace; white-space: nowrap;'>real(8, 3) NULL UNIQUE</font><br><em>Comment text</em><br><font style='font-family:monospace;'>1+1</font>")
 
 
 if __name__ == '__main__':