Australian model Kristy Hinze says she was instantly attracted to her 63-year-old boyfriend, Texan billionaire Jim Clark, by his intelligence.

The 27-year-old granddaughter of the late Queensland politician Russ Hinze has been dating Clark, the founder of Netscape, for two-and-a-half years.

The pair were tight-lipped about their relationship until now, but Hinze has told The Australian Women's Weekly she was instantly attracted to the thrice-married entrepreneur.