Katy Perry's Grammy special

Katy Perry and Justin Bieber are to perform at the Grammy Awards nomination special.

The two-time Grammy-winning rapper LL Cool J will host the one-hour special. titled 'Grammy Nominations Concert Live! Countdown To Music's Biggest Night'

The line up also features Bruno Mars, and rapper B.o.B.

The concert is set to be broadcast in the US on December 1st - with the awards ceremony itself on February 13th.