Christie Brinkley was in high spirits as she stepped out at a screening of her new film American Summer in the Hamptons with her two oldest children on Tuesday night.The 72-year-old supermodel looked half her age as she posed with daughter Alexa Ray Joel, 40, and son Jack Brinkley-Cook, 31, appearing more like a sibling than a mother. Brinkley looked summer chic in a Breton top and navy pants, leaving her famous blonde tresses loose and flowing. Joel, whose father is legendary singer-songwriter Billy Joel, rocked a leather jacket and strapless white top that emphasized her ample bust. Meanwhile, Brinkley-Cook, whose father is real estate developer Peter Taubman, cut a relaxed figure in a blue linen button down, carpenter pants and Birkenstock mules. The supermodel is also mother to a younger daughter, Sailor Brinkley-Cook, 28, who wasn’t in attendance at the event. Christie Brinkley was in high sprits as she stepped out at a screening of her new film American Summer in the Hamptons with her two oldest children on Monday The beauty defied her 72 years, looking positively youthful in a summery ensemble Last week, Brinkley left fans stunned when she posed with her youngest daughter at an event in Hamptons, with some mistaking the pair for twins. The youthful beauty recently opened up about aging in a recent interview.’I think that with age you get… freer,’ Brinkley told her Social Life Magazine cover story in June.’You do what you wanna do when you wanna do it. I think that there’s a freedom that comes with age that’s quite wonderful. You don’t really care what anybody thinks about your outfit anymore.’You know what you like. You know what you don’t like. And you don’t feel like you have to put up with the stuff that you don’t like anymore.’And while the life-long vegetarian has admitted to using ‘Botox in my forehead two times’ and laser treatments, she reportedly only gets injectable filler once a year on her marionette lines. Brinkley and youngest daughter Sailor wore matching blue denim outfits, accessorized with belts and boots last week The 72-year-old supermodel defied age as she posed on the carpet at The Stephen Talkhouse in Amagansett, NY Fans mistook Brinkley for her daughter as she struck a sexy pose in front of a retro red Ford F-100 truck in a recent Instagram carouselBrinkley, who has been married four times, is currently single. The Michigan-born, Malibu-raised beauty was first married to French artist François Allaux. They split in 1981. Brinkley welcomed her eldest Alexa during her nine-year marriage to five-time Grammy winner Billy Joel, which ended in 1994.She married real estate developer Peter Taubman that same year, before welcoming their son Jack in 1995. They split shortly after, with Brinkley tying the knot to architect Peter Cook in 1996. He helped to raise Jack, while the couple gave birth to their own child Sailor in 1998. Brinkley and Cook split a decade later. The supermodel stars in the family comedy American Summer, set to be released this coming Thursday, alongside Steve Gutenberg, who was also in attendance at the screening.