Current age: 29
Career at 20: Shia was known as a jokester, mostly due to his comedic role in the iconic Disney Channel show Even Stevens. He tried to outgrow his teenage image by starring in huge films like Disturbia and Transformers.
Relationship status at 20: Shia clearly wasn't looking to get tied down. He allegedly went on a date with Rihanna before getting romantically entangled with his Transformers costar Megan Fox.
Quoted at 20: In an interview in 2007, Shia was asked if he would always act, and he replied, "I'm 20, and there's so many possibilities. It would be insane for me to say, 'Yeah, this is definitely it; I'm never doing anything else.' I'm 20 years old. I don't know what I'm doing. I don't know anything about life. So I don't know."