diff --git a/src/environments/fancythm.pysty b/src/environments/fancythm.pysty
index 0e6ea82..e389ced 100644
--- a/src/environments/fancythm.pysty
+++ b/src/environments/fancythm.pysty
@@ -90,6 +90,8 @@ __LANGUAGE_OPTIONS_X__
 \DeclareOptionX{lecturenumbers}{\setkeys{__PACKAGE_NAME__}{__PACKAGE_PREFIX__lecturenumbers=#1}}
 \DeclareOptionX{numbersmallenvironments}{\setkeys{__PACKAGE_NAME__}{__PACKAGE_PREFIX__numbersmallenvironments=#1}}
 
+\DeclareOptionX{defaulttheorems}{\setkeys{__PACKAGE_NAME__}{__PACKAGE_PREFIX__defaulttheorems=#1}
+
 __END_OPTIONS_X__
 
 %%%%%%%% Implementation section