diff --git a/exercises/matrix/matrix.py b/exercises/matrix/matrix.py
index d6b14b504ed..3f2d3ab1ef8 100644
--- a/exercises/matrix/matrix.py
+++ b/exercises/matrix/matrix.py
@@ -1,3 +1,3 @@
 class Matrix(object):
-    def __init__(self):
+    def __init__(self, matrix_string):
         pass