diff --git a/bilby/core/sampler/cpnest.py b/bilby/core/sampler/cpnest.py
index 25183bd07eb53938b122bb0305b89b0c548d718d..544ec33260918d6e4ed155f601881fb62f98effc 100644
--- a/bilby/core/sampler/cpnest.py
+++ b/bilby/core/sampler/cpnest.py
@@ -89,8 +89,8 @@ class Cpnest(NestedSampler):
                 prior_samples = self.priors.sample()
                 self._update_bounds()
                 point = LivePoint(
-                    self.names, array.array(
-                        'f', [prior_samples[name] for name in self.names]))
+                    self.names, array.array('d', [prior_samples[name] for name in self.names])
+                )
                 return point
 
         self._resolve_proposal_functions()