Index: src/main/org/codehaus/groovy/runtime/wrappers/GroovyObjectWrapper.java
===================================================================
--- src/main/org/codehaus/groovy/runtime/wrappers/GroovyObjectWrapper.java	(revision 20234)
+++ src/main/org/codehaus/groovy/runtime/wrappers/GroovyObjectWrapper.java	(working copy)
@@ -62,6 +62,13 @@
   }
 
   /* (non-Javadoc)
+   * @see groovy.lang.GroovyObject#getMetaClass()
+   */
+  public MetaClass getMetaClass() {
+    return this.wrapped.getMetaClass();
+  }
+
+  /* (non-Javadoc)
    * @see groovy.lang.GroovyObject#setProperty(java.lang.String, java.lang.Object)
    */
   public void setProperty(final String property, final Object newValue) {
Index: src/test/groovy/bugs/Groovy4241Bug.groovy
===================================================================
--- src/test/groovy/bugs/Groovy4241Bug.groovy	(revision 0)
+++ src/test/groovy/bugs/Groovy4241Bug.groovy	(revision 0)
@@ -0,0 +1,22 @@
+package groovy.bugs
+
+class Groovy4241Bug extends GroovyTestCase {
+    void testAsTypeWithinvokeMethodOverridden() {
+        Foo4241.metaClass.invokeMethod = { String name, args ->
+            println name
+            for (arg in args) {
+                println arg.getClass()
+            }
+        }
+        def f = new Foo4241()
+        
+        def bar = [key: 'foo'] as Bar4241
+        f.echo(bar) // this used to work
+        
+        f.echo([key: 'foo'] as Bar4241) // this used to fail with NPE
+    }
+}
+
+class Foo4241 {}
+
+class Bar4241 {}