KFC has warned its 1.2 million Colonel's Club loyalty scheme members that their data may have been breached after its website was hacked.
The fast food giant emailed customers advising them to change their passwords following the attack.
Users of the loyalty scheme were told a "small number" of accounts "may have been compromised as a result of our website being targeted".
Customers who use the same email address and password for other services were advised to reset them "just to be safe".
The restaurant chain said it had introduced "additional security measures" in a bid to "safeguard our members' accounts", adding that it was "sorry for any inconvenience this may have caused".
KFC told ITV News that only 30 of its 1.2 million members had been targeted but that all customers had been informed.
Brad Scheiner, Head of IT at KFC UK & Ireland said: "We take the online security of our fans very seriously, so we’ve advised all Colonel’s Club members to change their passwords as a precaution, despite only a small number of accounts being directly affected.
"We don’t store credit card details as part of our Colonel’s Club rewards scheme, so no financial data was compromised."