Best and Worst Dressed at the 2015 Billboard Music Awards

Fresh off the announcement of her upcoming Las Vegas residency, J.Lo rocked the red carpet in a super-revealing sheer Charbel Zoe dress.

The Billboard Music Awards co-host had a lot of fabulous outfits over the course of the night. This black-and-white draped dress was not one of them.

The singer was pretty in purple as she performed her new single "Invincible."

Some of the boys looked a little schlubby at their first awards show appearance since the departure of Zayn Malik. Maybe Zayn was the true fashionista of the group?

The Orange is the New Black star sparkled in a white Marc Bouwer minidress with silver and Austrian crystalaccents.

The singer has often spoken about having synesthesia, a neurological condition where a person can see vibrant colors stimulated by their other senses. So what's with all the black?

The 47-year-old singer stunned in a short dark green dress when she presented the award for Best Male Artist.

Between the nude panel on her baby blue skirt and her pink tips, we're not sure what was going on with Iggy's washed-out look.

The model and "Bad Blood" music video star rocked a black and purple striped dress with a super-high thigh slit on the red carpet.