The "Sherlock Holmes" star dined with the blonde at a venue in Manhattan on April 19 and onlookers saw them kissing each other, New York Daily News reported.
But Law, 39, was clearly keen not to disclose anything about his love life and he refused all requests to pose for photos. "I'm in and I'm out, but it was good to see you, darling," he told one of his fans.
Law split from his fiancee, actress Sienna Miller, in 2006 after cheating on her with his children's nanny. They reconciled in 2009 but announced in February last year that they had split for good.