iHeartRadio Music Festival 2018: All the stars that were there!

Stars go to Vegas!

The 2018 iHeartRadio Music Festival kicked off at T-Mobile Arena on Friday night, and a slew of the biggest stars in music and TV were on-hand for the hottest party in Las Vegas this weekend.

Mariah Carey stole the show both onstage and on the red carpet, where she rocked a teeny studded black mini dress that showed off her slimmed-down figure. The "GTFO" singer was all smiles for her big night, where other stars like Sarah Hyland, Sara and Erin Foster and Paula Abdul were also in attendance.

Jack White, Fleetwood Mac and Childish Gambino were among the other musicians to take the stage.

Check out the gallery below for an updating roundup of the stars at the 2018 iHeartRadio Music Festival:

On Saturday night, Justin Timberlake and Shawn Mendes took the stage -- at one point, together! -- as did Kelly Clarkson and Carrie Underwood. Other stars there on the second night of the 2018 iHeartRadio Music Festival were the Bellas, K.J.Apa and more of the stars of "Riverdale" and Kristin Cavallari.