When Chadwick Boseman, Sienna Miller [1], and Stephan James stopped by The Late Late Show With James Corden [2] on Thursday, little did they know they'd have to justify some of their private cell phone activity in his game "Cell Phone Profile."

Ahead of the show, James's team collected data from one phone (with permission!) and shared a picture, an app, and a food order that provided some hints as to the owner's identity. The host then proceeded to grill the stars to find out who owned the phone, and there were some serious (and seriously bad) poker faces in play as he asked some tricky questions. Whoever it is, they're well-connected (the photo features three living legends) but surprisingly stingy when it comes to tipping delivery drivers. Can you work out whose phone it is before James makes his guess?