Lady Gaga performed “Summerboy” at her Mayhem Ball tour opener in Las Vegas Wednesday — its first live performance since 2007.

After making a big splash at Coachella and coming to Brazil back in the spring, Lady Gaga launched her global Mayhem Ball tour at T-Mobile Arena in Las Vegas Wednesday night. The career-spanning set ...

Lady Gaga kicked off her "Mayhem Ball" tour at T-Mobile Arena in Las Vegas on Wednesday, July 16th with a four-act, 27-song ...