"Big Bang Theory" star Kaley Cuoco has become a Hollywood "it girl" over the past few years.
You may think you know almost everything about the "Big Bang Theory" actress, but think twice.
Here are some surprising facts about the sitcom superstar:
1. Kaley wasn't the first choice for the 'Big Bang Theory'
Believe it or not, the main female character in the show was originally going to be played by Canadian actress Amanda Walsh.
According to the International Business Times, Walsh starred in the original pilot as the character Katie, but CBS rejected the show.
Eventually, the network picked up the show when Cuoco replaced Walsh as the now-popular character, Penny.
The rest is history.
2. She finished high school at 16
You can add Cuoco to the list of smart Hollywood celebrities.
According to IMDB, Cuoco was home-schooled and earned her diploma early at 16.
3. Kaley has a knack for horseback riding
Cuoco has been an avid horseback rider and trainer since she was 15 years old.
She recently posted a pic on Instagram of her kissing her horse Bojangles alongside her rumored boyfriend, Karl Cook. She wrote, "Not sure who I'll miss more."
4. Cuoco sings!
At the age of 25, Cuoco faced a scary fall during a horse riding accident.
While she was in the hospital with a leg fracture, Cuoco and her then-boyfriend Christopher French, of the group Annie Automatic, sang "Somewhere Over the Rainbow.”
The couple eventually recorded the song for the Human Society of the United States in support for animal adoption.
5. She is a former nationally-ranked tennis player
According to IMDB, before becoming an actress, she was a notable amateur tennis player who won several matches in the junior leagues nationally.
Cuoco was reportedly ranked sixth during the 2000 USA National Open Championship amongst junior and college tennis players. She still plays recreationally.
No wonder she connected with her ex-husband, Ryan Sweeting, a professional tennis player.
6. Kaley was Ellen DeGeneres?
That's right -- in a Degeneres' sitcom during the 1990s, Cuoco played a younger version of the comedian on "Ellen."
In episode 6 of season 4, Ellen and her childhood friend, Paige, played by Joely Fisher, go to the same summer camp they went to when they were kids.
With her hair cut short like Ellen, Cuoco plays the flashback version of Ellen as DeGeneres and her friend reminisce.
7. She voiced a dog
Cuoco was the voice behind the main character on the animated show "Brandy & Mr. Whiskers," on Disney Channel.
The show aired for two seasons from 2004 to 2006. The series followed Brandy, a tomboyish 14-year-old dog and her rabbit friend, Mr. Whiskers.