MGM Resorts International has revealed a data hack last summer that has compromised personal information of more than 10 million guests. The company says it ‘is confident’ no financial data such as payment card details or passwords were affected.

“Last summer, we discovered unauthorized access to a cloud server that contained a limited amount of information for certain previous guests of MGM Resorts”, a company spokesman said.

All the guests involved have been notified.

The hacked information includes names, emails and telephone numbers, and up to 1,000 may have had passport and drivers’ license details compromised.

Reportedly among those whose information was breached, were a number of high profile guests, celebrities and business leaders including Twitter CEO Jack Dorsey and entertainer Justin Bieber.

The hacked data was posted on a hacking forum this week.

MGM Resorts says it has beefed up its security and is working with two cybersecurity forensic firms to investigate the hack.