The fact that her agency, Sidus HQ, may have had Jeon's phone cloned to monitor her phone calls and text messages gives an insight into the darker side of the entertainment industry.

Markedly unequal contracts signed by entertainers and their agents are nothing new. They are labelled "slave contracts" because they relegate almost all authority to the agents at the expense of the entertainers' rights.

Entertainers who hope to make it big find it hard to refuse such contracts because it is difficult to launch a career in the entertainment industry without powerful agencies behind them.

Jeon signed up with Sidus HQ more than 10 years ago when she was in high school. There were rumours that she may not renew her contract, which expires next month, because she was unhappy with the agency for intruding on her personal life.

It is speculated that Sidus HQ may have eavesdropped on Jeon's cell phone to check if she was in contact with other agencies.

The Seoul police said it was investigating whether Sidus HQ had cloned other stars' phones. "We suspect this may have been the agents' usual way of controlling celebrities."

Celebrities complain that their agents control their lives excessively. One popular singer recently said that her agent constantly calls her to check her whereabouts. Of the 350 celebrities questioned by the Fair Trade Commission last year about "slave contracts", some 200 said that they were forced to report on their whereabouts even when they were not working. More than 100 said they had virtually no private life.

Agencies claim that such monitoring is necessary because they have made big investments in their stars and need to prevent celebrities defecting to another agency.

Powerful agencies and their money are behind Korea's top stars, including Hallyu stars. It could be posited that without these agencies, Korean stars may never have been able to reach beyond Korea's borders.

However, oppressive contracts and intrusions into personal life ultimately lead to unhappy stars. Conflicts between agents and celebrities no doubt have a negative impact on the entertainment industry.

The country's entertainment industry and the government are looking for ways to revive the popularity of Korean pop culture in other Asian countries, which has been declining steadily. Perhaps one way to inject new vitality is to break this oppressive system.