diff --git a/rest_framework/serializers.py b/rest_framework/serializers.py
index 5bd9b6473..e27610178 100644
--- a/rest_framework/serializers.py
+++ b/rest_framework/serializers.py
@@ -1010,7 +1010,7 @@ class ModelSerializer(Serializer):
                 continue
 
             extra_field_kwargs = extra_kwargs.get(field_name, {})
-            source = extra_field_kwargs.get('source') or field_name
+            source = extra_field_kwargs.get('source', '*') != '*' or field_name
 
             # Determine the serializer field class and keyword arguments.
             field_class, field_kwargs = self.build_field(