One Direction star Niall Horan.Wallko

Their private conversations have reportedly been stolen by the same hackers who targeted Sony's Hollywood film studios and delayed the release of 'The Interview'.

Details of the stars' contracts and demands are believed to be among the information stolen by the hackers - who have been traced to Pyongyang, North Korea by the FBI - and it could cause "embarrassment" for the singers.

Media analyst Mike Raia said: "The potential embarrassment and turmoil would be as devastating as that which has crippled Sony's movie-making arm and effectively killed the general release of 'The Interview'."

There is also a worry about the early release of music from some of the biggest artists at Sony Music - who own major record labels including Columbia, RCA and Epic - including David Bowie, 67, Rita Ora, 24 and Beyoncé, 33. Mike added to the Daily Star on Sunday: "Music files intended for release at a later date could be released on the net where fans would download them for free.

"We're talking about hundreds of millions of dollars in lost revenue.

It could end up as a financial disaster so enormous that the company, at least in its present form, might not even survive."

Meanwhile, a senior executive at Sony Music has claimed that bosses at the firm are "in complete panic" over the hacking.

The executive said: "We don't even know the extent of exactly what they have. We know it's a lot.

"There are skeletons in everyone's cupboard, only nobody ever expects a bunch of robbers to smash down the door and steal everything inside."