Before They Were Stars: Vin Diesel

Hard to believe it but Vin Diesel once had hair! Check out this '80s break-dancing instructional video where the Riddick star shows off some moves we didn't know he had...

Before They Were Stars: Michelle Williams

Fantastic bit of adolescent awkwardness. Hoff steals the moment with his reactions to his boy Hobie getting invited to the party.

Before They Were Stars: A Mega-Mix

25 fresh-faced pre-celebs in some rather embarrassing, perhaps best-forgotten roles you might have missed...

Before They Were Stars: Henry Thomas

The kid's totally in the zone. Awesome.

Before They Were Stars: Jake Gyllenhaal

Totally forgot that Jake Gyllenhaal was in City Slickers. Here's 11-year-old Jake in cowboy hat being interviewed on a British TV show. Cute overload warning.

Before They Were Stars: Michael Cera

Long before he was crowned the Prince of Awkward Geek Chic, here's Michael Cera playing a "mind assassin" in an episode of La Femme Nikita (is that show as bad as the clip makes it out to be??):

Before They Were Stars: Jason Reitman

He's not technically a "star" as such, but Jason Reitman, the director of Juno and Thank You For Smoking, got his first kiss on the set of Arnie's Kindergarten Cop (which was produced by his father Ivan) and it's been immortalised on youtube in all its dorky awkward adolescent glory. I guess there are worse things to be embarrassed about... (via InContention)

Before They Were Stars: Keanu Reeves

Keanu talking "bearness" on 80's Canadian kids TV show Going Great.