How to add a contact to People from Hangouts?

I'm using KitKat. I have Hangouts conversations with people who are not in my contacts (this may be an artifact of using a Google Apps account provided by my school). How can I add someone from one of these conversations to People? I have tried double-tapping and holding down their icon or their chats without any success, and looking at the "..." options menus. No luck. I do know how to add contacts from email.