Bruno Mars started off the iHeartRadio Music Festival in Las Vegas at The Bank Nightclub and GOLD Boutique Nightclub & Lounge on Friday night!

The seven-time Grammy nominee performed at The Bank at Bellagio Resort & Casino, where the crowd, which included Glee's Naya Rivera and Darren Criss, sang along to "Grenade" and "The Lazy Song."

Mars and pals partied until 3 a.m., then headed back their VIP suite.