Katy Perry has announced she has a new track with Alesso called ‘When I’m Gone’ coming later this month.Her team up with the Swedish EDM producer is set to arrive on December 29, the same day her ‘Play’ Las Vegas residency kicks off at the new Resorts World casino.“Don’t worry y’all, you’ll still be able to #PLAY along with me on December 29th, because #WHENIMGONE with @alesso will be coming,” she tweeted yesterday (December 15), seemingly directing her message at those who can’t make her Vegas