Kelly Clarkson & Adam Lambert Hit Up iHeartRadio Pool Party With Fellow 'Idol' Alum Katharine McPhee

Kelly Clarkson keeps it cute as she poses backstage ahead of her performance at the 2015 iHeartRadio Summer Pool Party held at Caesars Palace on Saturday (May 30) in Las Vegas.

The 33-year-old entertainer was joined by her fellow American Idol alums Adam Lambert and Katharine McPhee.

PHOTOS: Check out the latest pics of Kelly Clarkson

“Thanks everyone! See ya at the concert! #iHeartPoolParty #iheartadam,” Adam tweeted earlier in the day.

Watch some highlights from the star-studded concert below!

25+ pictures inside of Kelly Clarkson, Adam Lambert, and Katharine McPhee in Vegas…