Pop star Justin Bieber and Twitter CEO Jack Dorsey were among 10.6 million MGM Resorts guests to have their personal information exposed in a data breach last year, according to multiple reports.

U.S. government officials were also affected by the breach, which MGM Resorts has confirmed was discovered last summer. Tech blog ZDNet was first to report the breach Wednesday evening, after working with a data breach monitoring service to verify personal details published to a hacking forum earlier this week.