The Mack Nevada feat. Mark Morrison & Fetty Wap Download 'The Mack' on iTunes
The 'Last Friday Night' singer is leading the way for smurfs across the world.
Katy, who plays Smurfette in new movie The Smurfs, is appealing for people to join Global Smurf Day, taking place at London's O2 Arena this weekend.
The event encourages people to go blue from head to toe in a bid to break the record for the largest gathering of people dressed as Smurfs.
Get the dish in this video from Katy...
Find out more about Global Smurf Day on Saturday 25th June here.
The Smurfs hits cinemas in 3D on Wednesday 10th August, starring Katy Perry with How I Met Your Mother's Neil Patrick Harris and Glee's Jayma Mays.