diff --git a/sdv/data_processing/data_processor.py b/sdv/data_processing/data_processor.py
index bdbb02209..9bda9644e 100644
--- a/sdv/data_processing/data_processor.py
+++ b/sdv/data_processing/data_processor.py
@@ -483,6 +483,15 @@ def _create_config(self, data, columns_created_by_constraints):
                     )
                     sdtypes[column] = 'pii'
 
+            elif sdtype == 'unknown':
+                transformers[column] = AnonymizedFaker(
+                    function_name='bothify',
+                )
+                transformers[column].function_kwargs = {
+                    'text': 'sdv-pii-?????',
+                    'letters': '0123456789abcdefghijklmnopqrstuvwxyz'
+                }
+
             elif pii:
                 enforce_uniqueness = bool(column in self._keys)
                 transformers[column] = self.create_anonymized_transformer(
diff --git a/sdv/metadata/single_table.py b/sdv/metadata/single_table.py
index d56864806..18b2b3ebb 100644
--- a/sdv/metadata/single_table.py
+++ b/sdv/metadata/single_table.py
@@ -32,6 +32,7 @@ class SingleTableMetadata:
         'categorical': frozenset(['order', 'order_by']),
         'boolean': frozenset([]),
         'id': frozenset(['regex_format']),
+        'unknown': frozenset([]),
     }
 
     _DTYPES_TO_SDTYPES = {
diff --git a/tests/integration/single_table/test_copulas.py b/tests/integration/single_table/test_copulas.py
index 6b361ea02..ba5db4cd1 100644
--- a/tests/integration/single_table/test_copulas.py
+++ b/tests/integration/single_table/test_copulas.py
@@ -394,3 +394,25 @@ def test_categorical_column_with_numbers():
     unique_values = synthetic_data['category_col'].unique()
     assert np.isnan(unique_values).sum() == 1
     assert set(unique_values[~np.isnan(unique_values)]) == {1, 2}
+
+
+def test_unknown_sdtype():
+    """Test the ``unknown`` sdtype handling end to end."""
+    # Setup
+    data = pd.DataFrame({
+        'unknown': ['a', 'b', 'c'],
+        'numerical_col': np.random.rand(3),
+    })
+
+    metadata = SingleTableMetadata()
+    metadata.detect_from_dataframe(data)
+    metadata.update_column('unknown', sdtype='unknown')
+
+    synthesizer = GaussianCopulaSynthesizer(metadata)
+
+    # Run
+    synthesizer.fit(data)
+    synthetic_data = synthesizer.sample(5)
+
+    # Assert
+    assert synthetic_data['unknown'].str.startswith('sdv-pii-').all()
diff --git a/tests/unit/data_processing/test_data_processor.py b/tests/unit/data_processing/test_data_processor.py
index a2ae15b92..862c977a7 100644
--- a/tests/unit/data_processing/test_data_processor.py
+++ b/tests/unit/data_processing/test_data_processor.py
@@ -1056,7 +1056,9 @@ def test__create_config(self):
             'id_no_regex': ['ID_001', 'ID_002', 'ID_003'],
             'id_numeric': [0, 1, 2],
             'id_column': ['ID_999', 'ID_999', 'ID_007'],
-            'date': ['2021-02-01', '2022-03-05', '2023-01-31']
+            'date': ['2021-02-01', '2022-03-05', '2023-01-31'],
+            'unknown': ['a', 'b', 'c'],
+            'address': ['123 Main St', '456 Main St', '789 Main St']
         })
         dp = DataProcessor(SingleTableMetadata(), locales=locales)
         dp.metadata = Mock()
@@ -1081,7 +1083,9 @@ def test__create_config(self):
             'id_no_regex': {'sdtype': 'id'},
             'id_numeric': {'sdtype': 'id'},
             'id_column': {'sdtype': 'id'},
-            'date': {'sdtype': 'datetime', 'datetime_format': '%Y-%m-%d'}
+            'date': {'sdtype': 'datetime', 'datetime_format': '%Y-%m-%d'},
+            'unknown': {'sdtype': 'unknown'},
+            'address': {'sdtype': 'address', 'pii': False},
         }
 
         # Run
@@ -1104,7 +1108,9 @@ def test__create_config(self):
             'id_no_regex': 'text',
             'id_numeric': 'text',
             'id_column': 'pii',
-            'date': 'datetime'
+            'date': 'datetime',
+            'unknown': 'pii',
+            'address': 'categorical'
         }
 
         int_transformer = config['transformers']['created_int']
@@ -1124,13 +1130,15 @@ def test__create_config(self):
 
         assert isinstance(config['transformers']['int'], FloatFormatter)
         assert isinstance(config['transformers']['float'], FloatFormatter)
+
         anonymized_transformer = config['transformers']['email']
-        primary_regex_generator = config['transformers']['id']
         assert anonymized_transformer == 'AnonymizedFaker'
 
+        primary_regex_generator = config['transformers']['id']
+        assert primary_regex_generator == 'RegexGenerator'
+
         first_name_transformer = config['transformers']['first_name']
         assert first_name_transformer == 'AnonymizedFaker'
-        assert primary_regex_generator == 'RegexGenerator'
 
         datetime_transformer = config['transformers']['date']
         assert isinstance(datetime_transformer, UnixTimestampEncoder)
@@ -1166,6 +1174,18 @@ def test__create_config(self):
             False
         )
 
+        expected_kwargs = {
+            'text': 'sdv-pii-?????',
+            'letters': '0123456789abcdefghijklmnopqrstuvwxyz'
+        }
+        unknown_transformer = config['transformers']['unknown']
+        assert isinstance(unknown_transformer, AnonymizedFaker)
+        assert unknown_transformer.function_name == 'bothify'
+        assert unknown_transformer.function_kwargs == expected_kwargs
+
+        address_column_transformer = config['transformers']['address']
+        assert isinstance(address_column_transformer, UniformEncoder)
+
     def test_update_transformers_not_fitted(self):
         """Test when ``self._hyper_transformer`` is ``None`` raises a ``NotFittedError``."""
         # Setup