diff --git a/src/gui/symbology/qgsheatmaprendererwidget.cpp b/src/gui/symbology/qgsheatmaprendererwidget.cpp
index d757470764f6..35fabb0d14cb 100644
--- a/src/gui/symbology/qgsheatmaprendererwidget.cpp
+++ b/src/gui/symbology/qgsheatmaprendererwidget.cpp
@@ -101,6 +101,7 @@ QgsHeatmapRendererWidget::QgsHeatmapRendererWidget( QgsVectorLayer *layer, QgsSt
   mRadiusUnitWidget->setUnits( QgsUnitTypes::RenderUnitList() << QgsUnitTypes::RenderMillimeters << QgsUnitTypes::RenderPixels << QgsUnitTypes::RenderMapUnits
                                << QgsUnitTypes::RenderPoints << QgsUnitTypes::RenderInches );
   mWeightExpressionWidget->registerExpressionContextGenerator( this );
+  mWeightExpressionWidget->setAllowEmptyFieldName( true );
 
   if ( renderer )
   {