Is it possible to add another item to this data object without using user_meta?

I would like to just add one more item to this standard class object.

The item I want to add is [user_tel] below the [user_email].

[data] => stdClass Object
        (
            [ID] => 1
            [user_login] => josh
            [user_pass] => $P$BKeFc3LoEr3njndyv7b/SlLkvPZ.
            [user_nicename] => josh
            [user_email] => [email protected]
            [user_tel] => +44 (0) 7000 000 000
            [user_url] => 
            [user_registered] => 2018-11-08 20:05:34
            [user_activation_key] => 
            [user_status] => 0
            [display_name] => Josh Cranwell

Is this possible to do?