diff --git a/lib/interface.js b/lib/interface.js
index 2ca594d..6271930 100644
--- a/lib/interface.js
+++ b/lib/interface.js
@@ -143,6 +143,24 @@ function createAnonymousInterface( def )
  */
 function createNamedInterface( name, def )
 {
+    // if too many arguments were provided, it's likely that they're
+    // expecting some result that they're not going to get
+    if ( arguments.length > 2 )
+    {
+        throw Error(
+            "Expecting two arguments for named Interface definition; " +
+                arguments.length + " given."
+        );
+    }
+
+    // the definition must be an object
+    if ( typeof def !== 'object' )
+    {
+        throw TypeError(
+            "Unexpected value for named class definition; object expected"
+        );
+    }
+
     // add the name to the definition
     def.__name = name;
 
diff --git a/test/test-interface-name.js b/test/test-interface-name.js
index cfe5689..804678b 100644
--- a/test/test-interface-name.js
+++ b/test/test-interface-name.js
@@ -50,6 +50,27 @@ var common     = require( './common' ),
     {
         Interface( 'Foo', 'Bar' );
     }, TypeError, "Second argument to named interface must be the definition" );
+
+    // we should be permitted only two arguments
+    var args = [ 'Foo', {}, 'extra' ];
+    try
+    {
+        Interface.apply( null, args );
+
+        // we should not get to this line (an exception should be thrown due to
+        // too many arguments)
+        assert.fail(
+            "Should accept only two arguments when creating named interface"
+        );
+    }
+    catch ( e )
+    {
+        assert.notEqual(
+            e.toString().match( args.length + ' given' ),
+            null,
+            "Named interface error should provide number of given arguments"
+        );
+    }
 } )();