It was only a rehearsal - but Katy Perry never misses the chance to bring some glitz and glamour to the party!
The singer was dressed as a Christmas bauble as she practiced her routine for the Grammy nominations show in America.
She wore a silver Tutu complete with shiny festive decorations in her hair as she warmed up for her big performance.
With the Fireworks singer making such an effort for the rehearsals - keep and eye on the Newsround website for what she'll be wearing for her actual performance.
As well as Katy, the likes of Selena Gomez and man of the moment Justin Bieber will take to the stage and perform at the show tonight.