Sports Illustrated’s Hailey Clauson Turns 21, Celebrates in a Jaw-Dropping Gown

Sports Illustrated’s latest cover girl celebrated her 21st birthday with a bang in Sin City. READ: Get to Know Hailey Clauson, One of Sports Illustrated’s Newest Swimsuit Issue Cover Models Blonde bombshell Hailey Clauson, who is featured on this year’s Swimsuit Issue, along with plus-size model Ashley Graham and MMA fighter Ronda Rousey, celebrated Clauson becoming legal by dining and clubbing in Las Vegas. We were told by a source that the festivities started early Friday evening when the California native arrived at the Encore Resort at Wynn Las Vegas with 10 friends in tow. The group was spotted at Jardin, a restaurant known for offering comforting American fare, where Clauson indulged in a decadent "flower pot" dessert. (Because what girl doesn’t like flowers or dessert?) Saturday afternoon, Clauson and her friends visited Encore Beach Club, where they partied in a luxury private bungalow while flaunting their swimsuit bodies. Drinking Grey Goose and Jack Daniels cocktails, "the ladies mostly tanned on the daybeds,” reported a rep for the venue. WATCH: Why Hailey Clauson’s Grandma Ripped Up Her Sports Illustrated Swimsuit Issue The rep adds that on Saturday night, Clauson and company had dinner at celebrity hot-spot Andrea’s, where Hailey rocked a slinky lingerie-inspired gown. And such a ensemble needed to be seen, which is probably why she headed straight for the Encore Players Club. "Hailey and her friends poured Red Bull and vodka 'Jackpot' drinks from a large crystal decanter," says the rep. Finally, the party ended at Surrender Nightclub, where Clauson, after savoring Grey Goose cocktails, was surprised with a custom birthday cake. "The party went strong at Surrender until the wee hours of the morning," says Encore. In other words, it pays to be 21 a Sports Illustrated cover model. Check out the festivities (and Hailey's dress) below: