In honor of tonight's "The Big Bang Theory" season finale, let's throw it back to the '90s and revisit the early work of its now-famous cast.

Johnny Galecki and Kaley Cuoco now star on one of the biggest sit-coms ever, but before they became Penny and Leonard, they landed some TV guest spots as kids that will live forever in the land of re-runs and the internet.

Young Kaley can be found in an episode of "Northern Exposure," the Alaska-based early '90s series starring Rob Morrow and John Corbett. Isn't she just the cutest little thing?

And, in 1991, Johnny made an appearance on coming-of-age sit-com "Blossom," a show that happened to star another "Big Bang" actress, Miyam Bialik. Two throwbacks for the price of one!