Bikini Shot of the Day: Rihanna Heats Up Hawaii in Tiny Two-Piece

Singer sports sexy swimwear while on vacation with Chris Brown

Rihanna's trip to Oahu looks as if it was pretty relaxing, to say the least.

The sexy singer was spotted lounging by the pool on Friday, Feb. 22, while vacationing with Chris Brown as part of her 25th birthday celebration.

And, oh yeah, the pop star was wearing a bikini, too!

Decked out in a skimpy floral two-piece, the Grammy winner kindly showed off her winning curves.

Aloha!