Jennifer Lopez reportedly walked away from a fashion launch last week with $50,000 worth of borrowed jewellery.

The pop star - whose most controversial jewellery moment to date was the absence of her wedding ring at the Golden Globes in January - decided to keep an expensive piece of jewellery on loan from Swiss jeweller, Robert Mouawad.

According to sources, the singer assumed that the jewellery was for keeps as a 'thank you' for attending Andrea Lieberman's fashion launch party last week.

An insider told Page Six, "We received a call from [J.Lo's manager] Benny Medina, informing us that Jennifer was going to keep the jewellery. 

"As far as Mr. Mouawad is concerned, Jennifer can have whatever she wants, but a premature demand seemed presumptuous."

Mr Mouawad isn't going to press charges against Jennifer because, according to a jewellery insider, "Mr. Mouawad will lose no sleep over $50,000, and frankly, Jennifer's endorsement is priceless."

Jennifer's rep told Entertainmentwise, "This is not true and the jeweller said it wasn't true."

See Jennifer without her wedding ring at the Golden Globes below