Singer and actress Jennifer Lopez reacted angrily to rumours about her supposed engagement to 25 year old boyfriend Casper Smart.

"The Truth About the Ring.Rumors!!! Don't be fooled by the rocks that I got. No engagement!" the Latin diva wrote on her Web site. She also posted a photograph of herself in a white dress with a ring on her little finger (not her ring finger) and the comment: "How do you stop a false rumor?"

The speculation started after Lopez was seen with a large diamond ring. The ring, it was reported, cost several millions of pounds and she was seen wearing the 50.40-carat ring, designed by Cora Jewellers, during an episode of American Idol and, in fact, made sure it was prominent throughout the show.

"Having someone like Jennifer Lopez wear our ring, for me, is the ultimate. She represents a strong woman with a great sense of work ethic and intelligence. She is the American dream," Cora chief executive Suzette Gomes told People magazine; the report added that the rare yellow diamond was found in Africa and was set in 18-carat gold and ebony wood. The wooden element, according to the designers quoted in the report, was chosen to reflect the "from nature" aspect of the diamond itself.

The couple has been romantically linked since November and while there have been rumours before, the presence of the ring and tweets from celebrity fashion designers have only increased speculation. It now seems, though, tweets from the account of Italian designer Roberto Cavalli - stating Lopez had shown interest in a wedding dress - were false; the account had been hacked. However, the couple was photographed sharing intimate moments in Las Vegas.

The singer, who is preparing for a tour with Latin pop star Enrique Iglesias later this year, filed for divorce from ex-husband Marc Anthony in April. The couple was married for seven years.