diff --git a/fancy_gym/envs/mujoco/walker_2d_jump/walker_2d_jump.py b/fancy_gym/envs/mujoco/walker_2d_jump/walker_2d_jump.py
index fda511e..fe8d0b2 100644
--- a/fancy_gym/envs/mujoco/walker_2d_jump/walker_2d_jump.py
+++ b/fancy_gym/envs/mujoco/walker_2d_jump/walker_2d_jump.py
@@ -68,6 +68,8 @@ class Walker2dEnvCustomXML(Walker2dEnv):
                 low=-np.inf, high=np.inf, shape=(18,), dtype=np.float64
             )
 
+        self.observation_space = observation_space
+
         MujocoEnv.__init__(
             self,
             xml_file,