In April (12), a junior staff member quit her post after she was accused of passing 68 A-listers' details to London's Big Pictures photo agency, although she denied the allegations.
The airline has now confirmed the matter is being investigated by authorities at the Information Commissioner's Office.
A statement from Sir Richard Branson's company reads, "Following the allegations in the press in April, we voluntarily contacted the Information Commissioner's Office and have fully assisted with their enquiries.
"Our internal investigation found no evidence that this was anything other than an isolated incident relating to a single member of staff who is no longer with the business. We continue to treat the security of customer information extremely seriously and apologise to the passengers affected."
Stars who were reportedly affected include Rihanna, Gwyneth Paltrow, Daniel Radcliffe, Charlize Theron, Kate Winslet and Scarlett Johansson, among others.