diff --git a/pytorch_lightning/root_module/root_module.py b/pytorch_lightning/root_module/root_module.py
index b25ab9e4..fc8d62c5 100644
--- a/pytorch_lightning/root_module/root_module.py
+++ b/pytorch_lightning/root_module/root_module.py
@@ -247,6 +247,10 @@ class LightningModule(GradInformation, ModelIO, ModelHooks):
         for param in self.parameters():
             param.requires_grad = False
 
+        self.eval()
+
     def unfreeze(self):
         for param in self.parameters():
             param.requires_grad = True
+
+        self.train()