Fans Are Just Realizing That 'Big Bang's Johnny Galecki Is Rusty In 'Christmas Vacation'

We love when we see our favorite actors in roles we knew before we knew them. It's so fun to go back and watch old movies and television shows with new eyes, like when reruns of Roseanne are on and we all realized that our beloved Leonard from The Big Bang Theory was also the boy of our teenage dreams, David.

That probably wasn't the first thing you ever saw actor Johnny Galecki in, though!

Before they get their big break, celebrities still have to get work!

Unsplash | Jon Tyson

That's why so many actors and actresses have some pretty embarrassing early credits on their IMDb pages or show up in some pretty silly commercials!

Sometimes, though, those early roles are actually really cool.

Johnny Galecki is a very familiar face to us now.

After starring in one of the world's most popular sitcoms, The Big Bang Theory, for 12 seasons, I would sure hope so!

That's why this year when we all sat down and broke out the Christmas movie collection on December 1, so many of us had our eyes drawn to one character in particular.

He had a few roles before Leonard, of course.

Most notably was his appearance on Roseanne as David Healy, Darlene's adorable boyfriend.

Side note: Did you ever notice how many former Roseanne stars were on Big Bang? Darlene and Jackie also both made appearances as Leslie Winkle and Mary Cooper!

He also had a small role in the iconic movie *I Know What You Did Last Summer*.

That's right — Johnny met his unfortunate and tragic end at the hands of The Fisherman in the 1997 horror classic as Max!

But he was in something you've definitely seen, way before that.

You remember Rusty from *National Lampoon's Christmas Vacation*, right?

Russ was the adorable son and youngest child of the Griswold family in the iconic Christmas flick, but fans have just realized that this adorable little kid and Leonard Hofstadter are one and the same!

People are sharing this realization on Twitter.

"Every year I am reminded that Johnny Galecki is in National Lampoon's Christmas Vacation before I promptly forget only to say "Hey, that's Leonard!" the first time I see him on screen," shared one fan.

It's hard to recognize him without his glasses!

It's also hard to recognize him as a child, but I really think if Russ had some big dark frames we would've realized this whole thing a lot sooner.

Don't go looking for him in the other movies, though.

The Griswold children were played by different actors in most of the movies!

Luckily, Johnny got to be in what I consider to be the best one.

It goes to show that Johnny was part of our family traditions way before *Big Bang*, and we didn't even know it!

Unless of course you're more eagle-eyed than the rest of us and already knew that it was Johnny in the part.

Was this a new revelation to you, or did you always know? Let us know in the comments below!