diff --git a/python/plugins/processing/tests/AlgorithmsTestBase.py b/python/plugins/processing/tests/AlgorithmsTestBase.py
index af475f8fa97..0f0d4e3b82b 100644
--- a/python/plugins/processing/tests/AlgorithmsTestBase.py
+++ b/python/plugins/processing/tests/AlgorithmsTestBase.py
@@ -59,6 +59,7 @@ from processing.preconfigured.PreconfiguredAlgorithmProvider import Preconfigure
 
 from qgis.core import (QgsVectorLayer,
                        QgsRasterLayer,
+                       QgsMapLayer,
                        QgsProject,
                        QgsApplication,
                        QgsProcessingContext,
@@ -241,7 +242,10 @@ class AlgorithmsTest(object):
             if expected_result['type'] in ('vector', 'table'):
                 if 'compare' in expected_result and not expected_result['compare']:
                     # skipping the comparison, so just make sure output is valid
-                    result_lyr = QgsProcessingUtils.mapLayerFromString(results[id], context)
+                    if isinstance(results[id], QgsMapLayer):
+                        result_lyr = results[id]
+                    else:
+                        result_lyr = QgsProcessingUtils.mapLayerFromString(results[id], context)
                     self.assertTrue(result_lyr.isValid())
                     continue
 
@@ -254,7 +258,11 @@ class AlgorithmsTest(object):
                     except KeyError as e:
                         raise KeyError('Expected result {} does not exist in {}'.format(str(e), list(results.keys())))
 
-                    result_lyr = QgsProcessingUtils.mapLayerFromString(results[id], context)
+                    if isinstance(results[id], QgsMapLayer):
+                        assert False
+                        result_lyr = results[id]
+                    else:
+                        result_lyr = QgsProcessingUtils.mapLayerFromString(results[id], context)
 
                 compare = expected_result.get('compare', {})
 
diff --git a/src/core/processing/qgsprocessingparameters.cpp b/src/core/processing/qgsprocessingparameters.cpp
index cc06747a079..65b2512a609 100644
--- a/src/core/processing/qgsprocessingparameters.cpp
+++ b/src/core/processing/qgsprocessingparameters.cpp
@@ -277,6 +277,11 @@ QgsProcessingFeatureSource *QgsProcessingParameters::parameterAsSource( const Qg
     val = fromVar.source;
   }
 
+  if ( QgsVectorLayer *layer = qobject_cast< QgsVectorLayer * >( qvariant_cast<QObject *>( val ) ) )
+  {
+    return new QgsProcessingFeatureSource( layer, context );
+  }
+
   QString layerRef;
   if ( val.canConvert<QgsProperty>() )
   {
@@ -285,6 +290,11 @@ QgsProcessingFeatureSource *QgsProcessingParameters::parameterAsSource( const Qg
   else if ( !val.isValid() || val.toString().isEmpty() )
   {
     // fall back to default
+    if ( QgsVectorLayer *layer = qobject_cast< QgsVectorLayer * >( qvariant_cast<QObject *>( definition->defaultValue() ) ) )
+    {
+      return new QgsProcessingFeatureSource( layer, context );
+    }
+
     layerRef = definition->defaultValue().toString();
   }
   else
diff --git a/tests/src/core/testqgsprocessing.cpp b/tests/src/core/testqgsprocessing.cpp
index 94817a099ac..fa7f07c1573 100644
--- a/tests/src/core/testqgsprocessing.cpp
+++ b/tests/src/core/testqgsprocessing.cpp
@@ -3924,6 +3924,15 @@ void TestQgsProcessing::processingFeatureSource()
   QVERIFY( source->getFeatures().nextFeature( f2 ) );
   QCOMPARE( f2.geometry(), f.geometry() );
 
+  // direct map layer
+  params.insert( QStringLiteral( "layer" ), QVariant::fromValue( layer ) );
+  source.reset( QgsProcessingParameters::parameterAsSource( def.get(), params, context ) );
+  // can't directly match it to layer, so instead just get the feature and test that it matches what we expect
+  QVERIFY( source.get() );
+  QVERIFY( source->getFeatures().nextFeature( f2 ) );
+  QCOMPARE( f2.geometry(), f.geometry() );
+
+
   // next using property based definition
   params.insert( QStringLiteral( "layer" ), QgsProcessingFeatureSourceDefinition( QgsProperty::fromExpression( QStringLiteral( "trim('%1' + ' ')" ).arg( layer->id() ) ), false ) );
   source.reset( QgsProcessingParameters::parameterAsSource( def.get(), params, context ) );