Actress Cameron Diaz poses at the Women in Film 2008 Crystal and Lucy Awards in Beverly Hills, California June 17, 2008. The awards, presented by Women In Film, Los Angeles, honor outstanding women for their contribution to the entertainment industry. [Agencies]

Cameron Diaz has sparked speculation she is set to wed by sporting a diamond on her ring finger. The 'What Happens in Vegas' actress - who is dating British model Paul Sculfor - flashed the dazzling ring as she left Los Angeles' exclusive Nobu restaurant.

An onlooker said: "She wasn't hiding the ring and quite proudly showed it off." Earlier this week Cameron had been openly canoodling with new boyfriend Paul. The actress couldn't keep her hands off her new beau as they enjoyed a romantic meal in Hollywood before hitting the shops.

An onlooker said: "They kissed, held hands and walked with their arms around each other while shopping at the American Rag clothing store. They couldn't get enough of each other and didn't care who saw." The couple were first romantically linked earlier this month and have since enjoyed several dates. The pair were recently spotted at the exclusive Chateau Marmont hotel and Cameron appeared to be smitten with Paul, who previously dated Jennifer Aniston.

A source said: "Cameron and Paul were sitting on the patio, leaning in toward each other. Her body language looked like she was really comfortable with him. She looked genuinely like a girl falling in love."