The on and off couple, who controversially announced their reunion earlier this year, will marry in Barbados this July, reported Digital Spy.
Rihanna is planning on wearing a bikini at the ceremony rather than a wedding dress as she and Brown want to break with tradition, reported Digital Spy.
"This is her way to show the world that she does not care. Rihanna doesn't want a big dress or boring old confetti. She wants to get married in her bikini and have a carnival atmosphere. They want it to be relaxed and fun, like a 'playground', and to celebrate with the people who have stood by them," a source said.
The 25-year-old announced her reunion with her former boyfriend in January, insisting that it is important that she is "happy".
She has since said that Brown is not a "monster" despite his violent past. She sparked rumours of a wedding in February when she was seen wearing what appeared to be an engagement ring at the Grammy Awards.