Did he display that behavior from the beginning or is it just now showing up (baring his chest)? You say you have a good relationship with him for a year now. Have you had to put up with this that long? Yuck. I'd say you'll need to tell him that this is disturbing. Be careful that he doesn't turn it around to be your issue.

Also, telephone ringing is not kosher. It is an interruption and it is rude and it is unprofessional. Even if he doesn't answer the phone, it can seriously interrupt any sort of processing you're doing at the moment. Ask him to turn off his phone. No, tell him.