diff --git a/lib/mix/lib/mix/tasks/cmd.ex b/lib/mix/lib/mix/tasks/cmd.ex
index cfe43466db2..b4e3001e527 100644
--- a/lib/mix/lib/mix/tasks/cmd.ex
+++ b/lib/mix/lib/mix/tasks/cmd.ex
@@ -63,7 +63,7 @@ defmodule Mix.Tasks.Cmd do
       |> Enum.map(&String.to_atom/1)
 
     if apps != [] do
-      IO.warn("the --app in mix cmd is deprecated")
+      IO.warn("the --app in mix cmd is deprecated. Use mix do --app instead.")
     end
 
     if apps == [] or Mix.Project.config()[:app] in apps do