It’s almost impossible to imagine The Big Bang Theory without Kaley Cuoco. The actress is as synonymous with that show as jelly is to peanut butter, but in a new interview with TV Insider, Cuoco said she originally struggled to land the part of Penny because she was too young.

Hardcore fans of the CBS series know that before Cuoco was cast, The Big Bang Theory shot a pilot with a different love interest named Katie, played by actress Amanda Walsh. That character was a drunk, angry trainwreck—a far cry from Cuoco’s Penny.

They reconfigured the character as a flighty and lovable aspiring actress named Penny and brought Cuoco back in to audition after she failed to land the original role of Katie.

Credit: Sonja Flemming/CBS via Getty Images

In case you were curious, here’s a scene from that original pilot with the proto-Penny character:

In the same TV Insider interview, Johnny Galecki remembers reshooting the pilot with Cuoco.

The final episode of The Big Bang Theory will air on CBS on May 16th, 2019.