diff --git a/src/aks-preview/azext_aks_preview/custom.py b/src/aks-preview/azext_aks_preview/custom.py
index 48e5746cdda..5d59934c95b 100644
--- a/src/aks-preview/azext_aks_preview/custom.py
+++ b/src/aks-preview/azext_aks_preview/custom.py
@@ -1790,10 +1790,9 @@ def aks_update(cmd,     # pylint: disable=too-many-statements,too-many-branches,
             raise ArgumentUsageError('--disable-public-fqdn cannot be applied for none mode private dns zone cluster')
         instance.api_server_access_profile.enable_private_cluster_public_fqdn = False
 
-    if instance.auto_upgrade_profile is None:
-        instance.auto_upgrade_profile = ManagedClusterAutoUpgradeProfile()
-
     if auto_upgrade_channel is not None:
+        if instance.auto_upgrade_profile is None:
+            instance.auto_upgrade_profile = ManagedClusterAutoUpgradeProfile()
         instance.auto_upgrade_profile.upgrade_channel = auto_upgrade_channel
 
     if not enable_managed_identity and assign_identity: