Rihanna

25th Bday with Chris Brown

... and TINY BIKINI

2/21/2013 7:47 AM PST BY TMZ STAFF
breaking news
0221_rihanna_chris_brown_birthday_hawaii_launch_v3Rihanna turned 25 years old yesterday ... and she celebrated by throwing on one of her smallest bikinis and hitting a jet ski in Hawaii ... with Chris Brown.

RiRi and Brown spent the whole day together ... holding hands, jetting around in the ocean ... and probably smoking weed.

There were rumors that Brown was planning to pop the question during their Hawaii vacay ... but there doesn't appear to be a ring on her finger ... yet.