Atten-tion! One third of Major Lazer, Diplo, is here to school you in the fine art of looking fly in the foundation of any decent wardrobe: the plain white T-shirt.
Here he is performing during the Ultra Music Festival in Miami, while simultaneously offering a master class in how to rock a white tee. Not to tight, not too big, a little extra-length and roll the sleeves up a touch.
That's casual nailed, but if you want to smarten your look up a bit, go for a more fitted tee and throw a light (Major) blazer on top and finish with some smashing sunnies.