diff --git a/cmd/kubeadm/app/cmd/join.go b/cmd/kubeadm/app/cmd/join.go
index 93bfb63c63c..87670da9e2e 100644
--- a/cmd/kubeadm/app/cmd/join.go
+++ b/cmd/kubeadm/app/cmd/join.go
@@ -342,6 +342,9 @@ func newJoinData(cmd *cobra.Command, args []string, opt *joinOptions, out io.Wri
 
 	// if not joining a control plane, unset the ControlPlane object
 	if !opt.controlPlane {
+		if opt.externalcfg.ControlPlane != nil {
+			klog.Warningf("[preflight] WARNING: JoinControlPane.controlPlane settings will be ignored when %s flag is not set.", options.ControlPlane)
+		}
 		opt.externalcfg.ControlPlane = nil
 	}