The Vision Of Love singer, who also failed to deliver a good vocal performance, turned up in a very revealing black gown with a plunging neckline, mini-skirt front and long train at the back.
With her blonde hair flowing down in styled waves, Mariah also decided to wear shades. Why, we are not sure.
Rita Ora had a rare fashion fail in a trashy white outfit similar to Mariah’s which showed way too much skin and the matching white shoes were not a good choice. We know it’s Vegas, but no.
Ironically, the pair also teamed up before the event and took a selfie backstage with Reets posting it on Twitter, along with the caption: “So it happened yeeeeeaaahhhhhh baby great show@mariahcarey ain’t nobody wearing those diamonds like you.”
It appears to have been taken during rehearsals for the show as the duo are both in black gowns and Rita in a pair of daring knee-high boots.
Meanwhile, other stars on our Worst Dressed list tonight include singer Dencia who rocked up in a bizarre colourful one-piece and was mistaken by um, us, for Nikki Minaj on a first glance.
Britney Spears and Iggy Azalea, who are performing their duet Pretty Girls tonight also didn’t nail the red carpet look.
Awkwardly smiling for the paps, Britney wore a rather dull long pale pink gown but it wasn’t the worst we saw, while Iggy went for something more adventurous, a blue crop top and matching skirt.
The Australian rapper and singer, who is up for a number of awards tonight, paired it with bright pink heels and dip-dyed her hair to go with it.
We’ve also been quite strict and added Taraji P. Henson, Zendaya and Tracie Ellis Ross to the Worst Dressed List, along with Karen Fairchild, who wore a terrible leather outfit and thigh-high boots.
Despite the fashion fails, there were plenty of people who OWNED the red carpet and we will be listing them in our Best Dressed List.