diff --git a/lib/ansible/inventory/data.py b/lib/ansible/inventory/data.py
index dba7523bc4..43a044e4e8 100644
--- a/lib/ansible/inventory/data.py
+++ b/lib/ansible/inventory/data.py
@@ -231,7 +231,7 @@ class InventoryData(object):
         else:
             h = self.hosts[host]
 
-        if g and host not in g.get_hosts():
+        if g and h not in g.get_hosts():
             g.add_host(h)
             self._groups_dict_cache = {}
             display.debug("Added host %s to group %s" % (host, group))
diff --git a/lib/ansible/inventory/group.py b/lib/ansible/inventory/group.py
index 3469b360f7..dd90c97ea6 100644
--- a/lib/ansible/inventory/group.py
+++ b/lib/ansible/inventory/group.py
@@ -112,7 +112,8 @@ class Group:
             raise AnsibleError("The group named '%s' has a recursive dependency loop." % self.name)
 
     def add_host(self, host):
-
+        if host in self.hosts:
+            return
         self.hosts.append(host)
         host.add_group(self)
         self.clear_hosts_cache()