Rihanna 'debuts new song at Jay-Z gig'

Rihanna appeared alongside Jay-Z at his Los Angeles concert on Sunday and took to the stage to debut new song 'Hard'.

The singer joined the rapper during his show at the University of California, where they also performed their hit single 'Run This Town'.

According to Contactmusic, Rihanna's surprise showing was warmly received by the crowd, and she showed her appreciation by premiering a brand new track for the audience.

The gig marked the star's first live appearance since her TV interview with newswoman Diane Sawyer, in which she revealed details about her altercation with ex-boyfriend Chris Brown.

Rihanna is due to premiere more new material from her forthcoming album Rated R at a secret concert in London next Monday.