diff --git a/GPy/likelihoods/Gaussian.py b/GPy/likelihoods/Gaussian.py
index 17696939..71d755ed 100644
--- a/GPy/likelihoods/Gaussian.py
+++ b/GPy/likelihoods/Gaussian.py
@@ -51,6 +51,7 @@ class Gaussian(likelihood):
         return ["noise_variance"]
 
     def _set_params(self, x):
+        x = float(x)
         if self._variance != x:
             self.precision = 1. / x
             self.covariance_matrix = np.eye(self.N) * x