The Transformation Of Kaley Cuoco From Childhood To The Big Bang Theory.

When CBS’ “The Big Bang Theory” premiered in 2007, Kaley Cuoco captured fans’ hearts as neighbor-to-the-nerds Penny, a character she says is a lot like herself. “She’s just so loud and basically like me,” she told ET Online. “She’s all over the place…”

But you don’t get a permanent spot on a sitcom that goes on for 12 seasons — and win multiple awards for your performance — without serious acting chops.

Cuoco may have appeared to be a naïve newcomer when she first showed her sweet and smiling face on “The Big Bang Theory,” but like her character, she put years of work into honing her skills, defining her goals, and finally, reaching them. And it all started when she was only five years old.

“I basically grew up on stages and grew up in front of the camera, and I always kind of loved it,” she told Sidewalks. “My parents said, ‘Do it or don’t.’ It was never a big deal. … It was like another activity that we did. … It just kind of kept happening, and I kept working.”

Acting was a fun pastime for Cuoco as a youngster, but over time, she started landing high-profile parts. Here’s how she grew from a child actor into her most famous role to date.

Kaley Cuoco had plenty of interests as a child. She played tennis from age three, and she also enjoyed modeling and acting. Some of her earliest commercials were for Barbie and Oscar Meyer, when she was about five years old.

Her television debut came in 1992, when she was cast as Connie Reinhardt in a made-for-TV movie. “Quicksand: No Escape” told the story of a man who is framed for murder.

At just seven years old, she joined an amazing cast, including Donald Sutherland, Tim Matheson, and Felicity Huffman.

From there, Cuoco’s career was set in motion, and she began landing roles on some of the decade’s most popular shows.

In 1994, she appeared in an episode of CBS’ “Northern Exposure.” She also had a guest spot on ABC’s “My So-Called Life.” Two years later, she was on ABC’s “Ellen,” playing a young version of Ellen DeGeneres’ character.