Nerd Alert: What The Big Bang Theory Actors Looked Like As Kids

Of course you have. And fortunately, these stars have taken to Instagram to show us what a bunch of little cuties they were!

And first up, it is, of course, Jim Parsons who played Sheldon Cooper.

If you didn't already know Parsons was a child of the 70s, this photo of him certainly gives it away. The big hair, orange sweater and…well everything about his mother, give it away.

And (just like Sheldon) he looks a little awkward and is not quite managing to give his sister a proper cuddle.

And this is Melissa Rauch (Bernadette Rostenkowski-Wolowitz) showing just about everything that was fashionable in the 80s. The bow, the pastel shades, the pink earrings and, once again, the hair that defined a decade; they're all on display along with that cheeky smile.

Having a whale of a time and, naturally, all in dark, this is Mayim Bialik (Amy Farrah Fowler) as a child.

One from the family holiday album. But could you guess which Big Bang Theory star is at Niagara Falls? Well, the little lad in the bottom corner is Johnny Galecki who went on to star as Leonard Hofstadter.

And who's this little champion posing alongside her little sister? None other than Kaley Cuoco who grew up to win many more awards – 4 of them for playing Penny Hofstadter in TBBT. She even has a star on the Hollywood Walk of Fame.

And last but not least, the ever-popular Kunal Nayyar (Raj Koothrappali). Seen here in a classic red all-in-one outfit that was all the rage for babies born at the turn of the 80s, this little lad simply couldn't look any cuter.

So, there you have it. The stars of The Big Bang Theory before many of them had ever dreamed they might one day appear in one of the biggest sitcoms to ever air on TV.