they are doing 2-song medley, according to a billboard article... we know Trent sings at least one of them, from that rehearsal photo earlier today.
http://www.fleetwoodmacnews.com/2014...09946208107892
Grohl, Reznor, QOTSA and Lindsey Buckingham to perform 2 song medley
Dave Grohl, Trent Reznor Rock Hard at GRAMMY Rehearsals
Photo: David Wild @Wildaboutmusic
By Phil Gallo
The Reznor-Grohl-QOTSA outfit took the stage and spent a good 15 minutes getting the drum and electronics sound correct before rehearsing the song.
They, like all of the 21 scheduled performances, run through the song four times. They then bring in the lights, camera and effects for another four run-throughs.
A voice boomed over the PA -- "Dave wants more shaker" -- after one run-through and as they set about building their two-song medley (GRAMMY organizers want us to keep it a secret), they very loudly applied one layer atop the other.
Full article at Billboard