Madonna and RihannaRihanna has been announced as the latest addition to promote the coconut water brand Vita Coco's growing roster of pop star endorsers.

The singer joins investors Madonna and Red Hot Chili Peppers frontman Anthony Kiedis, both of whom are staunch advocates of the brand.

Beginning this summer, the red-coiffed 'California King Bed' singer will take part in a national advertising campaign for the product -- also noted as a hangover helper -- of which she claims to be quite a fan.

"I love Vita Coco! It's real coconut water from hand-picked coconuts," Rihanna said in a press release announcing the partnership. "It's delicious and so good for you!"