Rihanna is suing Topshop for $5 million.

The 'Diamonds' hitmaker is taking legal action against the UK high street fashion chain - which is owned by billionaire Sir Philip Green - following eight months of unsuccessful negotiations over T-shirts bearing her image which are being sold without her consent.

A source told the New York Post newspaper: ''Rihanna's management asked Topshop a number of times to stop selling her image and were told, 'We do what we want.' They buy the pictures from a photographer, but they do not pay the artist licensing fees. Unfortunately, UK law does not protect the artist.

''What is most offensive for Rihanna is that they basically told her, 'Go to hell. We don't care; we are going to continue selling you.' ''They offered her $5,000 and said they don't care.''

The 25-year-old singer has hired international law firm Reed Smith to file the suit in London, as the garments are only being sold in the UK, where the image rights are owned by the photographer who took the picture.

The source continued: ''Topshop is now in the United States. They set up in Manhattan and Nordstrom, but they know better than to do this in the US because they would get in trouble.

''Even though the UK laws don't protect the artist, she has decided to move forward and sue Topshop. She has spent almost $1 million in litigation at this point. She says it's the principle, and wants to make a statement about it. They are taking advantage of artists. It is just exploitation. What they are doing is wrong.''

The case is now in the discovery stage and Rihanna has handed over details of her deals with fashion house Armani and high street chain River Island.

Though no official spokesperson has commented on the case, a Topshop source said: ''This issue is related to a T-shirt provided to Topshop by a third-party supplier. We are aware it is the subject of litigation. [There are] public documents available for inspection in the London court.

''The amount of damages sought has not been articulated anywhere in the claimant's document.''