Ali Lohan showed off her pencil-thin figure while on a vacation in Hawaii with sister Lindsay Lohan. The 17-year-old model is on the island of Oahu, and was spotted in super-short cut-off jeans and a midriff-baring tank top and she looked so sexy. Earlier in the week, Ali attended a casting call in Beverly Hills. Ali, who towers over Lindsay, turns 18 December 22. She so far hasn't commented on Lindsay's Playboy pictorial which was leaked on the Internet. Lindsay was reportedly paid one million dollar to shoot the cover!