The 37-year-old actress posted her high school portrait on Twitter today as part of Throwback Thursday.
The beautiful blonde played a high school student for much of her early film career, with her breakout role in the 1999 film "Varsity Blues" as Paul Walker's cheerleader girlfriend Darcy. She also played a student in "Drive Me Crazy" and "Final Destination."
But she's best known for playing twins Niki and Tracy Strauss on "Heroes." Nowadays, Ali has another role, mom. She gave birth to son Theodore in 2010.
Getting her body back to pre-baby shape wasn't easy. After gaining 45 pounds, Ali had to rely upon food delivery services and lots of exercise to lose weight. "I tend to work out for an hour about four days a week, and I love to run," she told Health this month. "It's the quickest way, with my busy schedule, to be able to enjoy my life and keep my weight at where I want it to be. Sometimes I grab a trashy magazine and hit the treadmill."
To see even more celebrities before the fame, click on the "Launch Gallery" link above!