The infamous supermodel - who turns 38 today! - celebrated her birthday aboard Diddy's yacht in Cannes last night...

Naomi seemed to be having a good time for most of the night, but left noticeably moody. Just what happened on the yacht?!

The Daily Mail reports that she and Diddy have "a history of confrontation" - for example, the music mogul shouted at her during a Grammy after party in LA last year.

Let's hope whatever happened between them didn't spoil her b-day bash!