diff --git a/src/core/processing/qgsprocessingparameters.cpp b/src/core/processing/qgsprocessingparameters.cpp
index 9d57fef7033b..bf4b26f74482 100644
--- a/src/core/processing/qgsprocessingparameters.cpp
+++ b/src/core/processing/qgsprocessingparameters.cpp
@@ -2692,12 +2692,10 @@ QString QgsProcessingParameterDefinition::valueAsStringPrivate( const QVariant &
         return QString();
       case QgsProperty::StaticProperty:
         return valueAsString( prop.staticValue(), context, ok );
-
-      // these are not supported for serialization
       case QgsProperty::FieldBasedProperty:
+        return QStringLiteral( "field:%1" ).arg( prop.field() );
       case QgsProperty::ExpressionBasedProperty:
-        QgsDebugMsg( QStringLiteral( "could not convert expression/field based property to string" ) );
-        return QString();
+        return QStringLiteral( "expression:%1" ).arg( prop.expressionString() );
     }
   }
 
diff --git a/src/core/processing/qgsprocessingparametertypeimpl.h b/src/core/processing/qgsprocessingparametertypeimpl.h
index 863367261a3d..28597fb434c5 100644
--- a/src/core/processing/qgsprocessingparametertypeimpl.h
+++ b/src/core/processing/qgsprocessingparametertypeimpl.h
@@ -292,7 +292,9 @@ class CORE_EXPORT QgsProcessingParameterTypeBoolean : public QgsProcessingParame
     QStringList acceptedStringValues() const override
     {
       return QStringList() << QObject::tr( "1 for true/yes" )
-             << QObject::tr( "0 for false/no" );
+             << QObject::tr( "0 for false/no" )
+             << QObject::tr( "field:FIELD_NAME to use a data defined value taken from the FIELD_NAME field" )
+             << QObject::tr( "expression:SOME EXPRESSION to use a data defined value calculated using a custom QGIS expression" );
     }
 };
 
@@ -1124,7 +1126,9 @@ class CORE_EXPORT QgsProcessingParameterTypeString : public QgsProcessingParamet
 
     QStringList acceptedStringValues() const override
     {
-      return QStringList() << QObject::tr( "String value" );
+      return QStringList() << QObject::tr( "String value" )
+             << QObject::tr( "field:FIELD_NAME to use a data defined value taken from the FIELD_NAME field" )
+             << QObject::tr( "expression:SOME EXPRESSION to use a data defined value calculated using a custom QGIS expression" );
     }
 };
 
@@ -1330,7 +1334,9 @@ class CORE_EXPORT QgsProcessingParameterTypeNumber : public QgsProcessingParamet
 
     QStringList acceptedStringValues() const override
     {
-      return QStringList() << QObject::tr( "A numeric value" );
+      return QStringList() << QObject::tr( "A numeric value" )
+             << QObject::tr( "field:FIELD_NAME to use a data defined value taken from the FIELD_NAME field" )
+             << QObject::tr( "expression:SOME EXPRESSION to use a data defined value calculated using a custom QGIS expression" );
     }
 };
 
@@ -1382,7 +1388,9 @@ class CORE_EXPORT QgsProcessingParameterTypeDistance : public QgsProcessingParam
 
     QStringList acceptedStringValues() const override
     {
-      return QStringList() << QObject::tr( "A numeric value" );
+      return QStringList() << QObject::tr( "A numeric value" )
+             << QObject::tr( "field:FIELD_NAME to use a data defined value taken from the FIELD_NAME field" )
+             << QObject::tr( "expression:SOME EXPRESSION to use a data defined value calculated using a custom QGIS expression" );
     }
 };
 
@@ -1434,7 +1442,9 @@ class CORE_EXPORT QgsProcessingParameterTypeDuration : public QgsProcessingParam
 
     QStringList acceptedStringValues() const override
     {
-      return QStringList() << QObject::tr( "A numeric value (unit type set by algorithms)" );
+      return QStringList() << QObject::tr( "A numeric value (unit type set by algorithms)" )
+             << QObject::tr( "field:FIELD_NAME to use a data defined value taken from the FIELD_NAME field" )
+             << QObject::tr( "expression:SOME EXPRESSION to use a data defined value calculated using a custom QGIS expression" );
     }
 };
 
@@ -1753,7 +1763,9 @@ class CORE_EXPORT QgsProcessingParameterTypeColor : public QgsProcessingParamete
 
     QStringList acceptedStringValues() const override
     {
-      return QStringList() << QObject::tr( "String representation of color, e.g #ff0000 or rgba(200,100,50,0.8)" );
+      return QStringList() << QObject::tr( "String representation of color, e.g #ff0000 or rgba(200,100,50,0.8)" )
+             << QObject::tr( "field:FIELD_NAME to use a data defined value taken from the FIELD_NAME field" )
+             << QObject::tr( "expression:SOME EXPRESSION to use a data defined value calculated using a custom QGIS expression" );
     }
 };
 
@@ -1908,7 +1920,9 @@ class CORE_EXPORT QgsProcessingParameterTypeDateTime : public QgsProcessingParam
 
     QStringList acceptedStringValues() const override
     {
-      return QStringList() << QObject::tr( "A datetime value in ISO format" );
+      return QStringList() << QObject::tr( "A datetime value in ISO format" )
+             << QObject::tr( "field:FIELD_NAME to use a data defined value taken from the FIELD_NAME field" )
+             << QObject::tr( "expression:SOME EXPRESSION to use a data defined value calculated using a custom QGIS expression" );
     }
 };
 
diff --git a/src/core/processing/qgsprocessingutils.cpp b/src/core/processing/qgsprocessingutils.cpp
index 34f0f6c69597..201ac3e26aa7 100644
--- a/src/core/processing/qgsprocessingutils.cpp
+++ b/src/core/processing/qgsprocessingutils.cpp
@@ -1411,6 +1411,23 @@ QVariantMap QgsProcessingUtils::preprocessQgisProcessParameters( const QVariantM
         output.insert( it.key(), it.value() );
       }
     }
+    else if ( it.value().type() == QVariant::String )
+    {
+      const QString stringValue = it.value().toString();
+
+      if ( stringValue.startsWith( QLatin1String( "field:" ) ) )
+      {
+        output.insert( it.key(), QgsProperty::fromField( stringValue.mid( 6 ) ) );
+      }
+      else if ( stringValue.startsWith( QLatin1String( "expression:" ) ) )
+      {
+        output.insert( it.key(), QgsProperty::fromExpression( stringValue.mid( 11 ) ) );
+      }
+      else
+      {
+        output.insert( it.key(), it.value() );
+      }
+    }
     else
     {
       output.insert( it.key(), it.value() );
diff --git a/tests/src/analysis/testqgsprocessing.cpp b/tests/src/analysis/testqgsprocessing.cpp
index c97aa73aee9c..6858074aa9a4 100644
--- a/tests/src/analysis/testqgsprocessing.cpp
+++ b/tests/src/analysis/testqgsprocessing.cpp
@@ -396,6 +396,14 @@ class DummyAlgorithm : public QgsProcessingAlgorithm
       params.insert( "p2", QStringLiteral( "thisisa'test" ) );
       QCOMPARE( asQgisProcessCommand( params, context, ok ), QStringLiteral( "qgis_process run test --distance_units=meters --p1=a --p2='thisisa'\\''test'" ) );
       QVERIFY( ok );
+
+      addParameter( new QgsProcessingParameterString( "dd_field", QString(), true ) );
+      addParameter( new QgsProcessingParameterString( "dd_expression", QString(), true ) );
+
+      params.insert( "dd_field", QgsProperty::fromField( QStringLiteral( "my field" ) ) );
+      params.insert( "dd_expression", QgsProperty::fromExpression( QStringLiteral( "\"some field\" * 200" ) ) );
+      QCOMPARE( asQgisProcessCommand( params, context, ok ), QStringLiteral( "qgis_process run test --distance_units=meters --p1=a --p2='thisisa'\\''test' --dd_field='field:my field' --dd_expression='expression:\"some field\" * 200'" ) );
+      QVERIFY( ok );
     }
 
     void runAsAsJsonMapChecks()
@@ -11679,6 +11687,8 @@ void TestQgsProcessing::preprocessParameters()
   inputs.insert( QStringLiteral( "string" ), QStringLiteral( "a string" ) );
   inputs.insert( QStringLiteral( "data defined field" ), QVariantMap( {{QStringLiteral( "type" ), QStringLiteral( "data_defined" )}, {QStringLiteral( "field" ), QStringLiteral( "DEPTH_FIELD" ) }} ) );
   inputs.insert( QStringLiteral( "data defined expression" ), QVariantMap( {{QStringLiteral( "type" ), QStringLiteral( "data_defined" )}, {QStringLiteral( "expression" ), QStringLiteral( "A_FIELD * 200" ) }} ) );
+  inputs.insert( QStringLiteral( "data defined field using string" ), QStringLiteral( "field:MY FIELD" ) );
+  inputs.insert( QStringLiteral( "data defined expression using string" ), QStringLiteral( "expression:SOME_FIELD * 2" ) );
   inputs.insert( QStringLiteral( "invalid" ), QVariantMap( {{QStringLiteral( "type" ), QStringLiteral( "data_defined" )}} ) );
 
   bool ok = false;
@@ -11697,8 +11707,12 @@ void TestQgsProcessing::preprocessParameters()
   QCOMPARE( outputs.value( QStringLiteral( "string" ) ).toString(), QStringLiteral( "a string" ) );
   QCOMPARE( outputs.value( QStringLiteral( "data defined field" ) ).value< QgsProperty >().propertyType(), QgsProperty::FieldBasedProperty );
   QCOMPARE( outputs.value( QStringLiteral( "data defined field" ) ).value< QgsProperty >().field(), QStringLiteral( "DEPTH_FIELD" ) );
+  QCOMPARE( outputs.value( QStringLiteral( "data defined field using string" ) ).value< QgsProperty >().propertyType(), QgsProperty::FieldBasedProperty );
+  QCOMPARE( outputs.value( QStringLiteral( "data defined field using string" ) ).value< QgsProperty >().field(), QStringLiteral( "MY FIELD" ) );
   QCOMPARE( outputs.value( QStringLiteral( "data defined expression" ) ).value< QgsProperty >().propertyType(), QgsProperty::ExpressionBasedProperty );
   QCOMPARE( outputs.value( QStringLiteral( "data defined expression" ) ).value< QgsProperty >().expressionString(), QStringLiteral( "A_FIELD * 200" ) );
+  QCOMPARE( outputs.value( QStringLiteral( "data defined expression using string" ) ).value< QgsProperty >().propertyType(), QgsProperty::ExpressionBasedProperty );
+  QCOMPARE( outputs.value( QStringLiteral( "data defined expression using string" ) ).value< QgsProperty >().expressionString(), QStringLiteral( "SOME_FIELD * 2" ) );
 
   // test round trip of data defined parameters
   const QgsProcessingAlgorithm *bufferAlg = QgsApplication::processingRegistry()->algorithmById( "native:buffer" );
diff --git a/tests/src/python/test_qgsprocessexecutable_pt2.py b/tests/src/python/test_qgsprocessexecutable_pt2.py
index f679d4808494..b0d400120b2d 100644
--- a/tests/src/python/test_qgsprocessexecutable_pt2.py
+++ b/tests/src/python/test_qgsprocessexecutable_pt2.py
@@ -306,6 +306,19 @@ def testLoadLayer(self):
         self.assertEqual(rc, 1)
 
     def testDynamicParameters(self):
+        output_file = self.TMP_DIR + '/dynamic_out2.shp'
+
+        rc, output, err = self.run_process(
+            ['run', 'native:buffer', '--INPUT=' + TEST_DATA_DIR + '/points.shp', '--OUTPUT=' + output_file, '--DISTANCE=field:fid', '--json'])
+        self.assertFalse(self._strip_ignorable_errors(err))
+
+        self.assertEqual(rc, 0)
+
+        res = json.loads(output)
+        self.assertEqual(res['algorithm_details']['id'], 'native:buffer')
+        self.assertEqual(res['inputs']['DISTANCE'], 'field:fid')
+
+    def testDynamicParametersJson(self):
         output_file = self.TMP_DIR + '/dynamic_out.shp'
 
         params = {