17 November 2011, 08:52
The two US stars will join Lady Gaga and Ludacris for the industry award ceremony's live nominations broadcast.
Rihanna and Usher will perform at the Grammy Awards 2012 live nominations ceremony later this month.
The 'We Found Love' star has been confirmed for a performance on CBS' The Grammy Nominations Concert Live!, which will air on 30th November, while 'Without You' singer Usher has also been added to the show's bill.
The two join a star-studded line-up for the event including Lady Gaga, Ludacris, Lupe Fiasco and country band Sugarland.
The one-hour broadcast, hosted by LL Cool J, will unveil the names of the nominees for next year's Grammy Awards, due to take place in Los Angeles on 12th February, 2012.
RiRi flew back to the US yesterday (16th November) for her debut performance on The X Factor USA tonight, although she is due back in the UK this weekend to perform on The X Factor results show.
Rihanna released her new single 'You Da One' on Sunday (13th November) and sixth studio album 'Talk That Talk' will follow on 21st November.