Link to the thread on 'child actors who played young stars'.

Brad Renfro -- former child (and then not-child) star of The Client, Tom and Huck, Sleepers (in which he played the young Brad Pitt), Apt Pupil, Ghost World, etc. -- was found dead at his home. He was 25.

FWIW, I find the news especially sobering because Renfro's birthday was identical (though off by a few years) to someone I know who has also had drug problems lately.