Former supermodel Christie Brinkley is splitting from her fourth husband, architect Peter Cook. The estranged couple have been married for nearly 10 years and have eight-year-old daughter SAILOR LEE. Brinkley's spokesperson Elliot Mintz confirmed the split to US TV show Entertainment Tonight: "Yes, it's true. The couple has separated. "Christie's primary interest at this difficult time is for the protection of her children and (she) would be most appreciative if people would be good enough to respect her privacy." The 52-year-old model, who appeared in the 1980s comedy NATIONAL LAMPOON'S VACATION with Chevy Chase, has two other children from her previous marriages - ALEXA, 20, and 11-year-old JACK. She was previously married to PIANO MAN singer Billy Joel for nearly ten years and he wrote his hit Uptown Girl about her. Brinkley was also married to JEAN-FRANCOIS ALLAUX from 1973 until 1981, and RICHARD TAUBMAN from 1994 to 1995.