Kaley Cuoco: 5 Things to Know About the Teen Choice Awards Host

Kaley Cuoco Headshot Globes - P 2011
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BEVERLY HILLS, CA - JANUARY 16:  Actress Kaley Cuoco arrives at the 68th Annual Golden Globe Awards held at The Beverly Hilton hotel on January 16, 2011 in Beverly Hills, California. 

The actress kept her relationship with a ‘Big Bang Theory’ costar a secret for more than two years; she acted as the younger Ellen Degeneres on her ABC show ‘Ellen.’

Kaley Cuoco has lived her life on screen since she was a child, first appearing in the TV movie Quicksand: No Escape with Donald Sutherland. This Sunday she follows in the footsteps of Katy Perry, Jonas Brothers, Miley Cyrus and David Spade as she hosts the 11th Annual Teen Choice Awards on Fox. Here are five facts about The Big Bang Theory and 8 Simple Rules actress you may not have known.

1. Cuoco was not originally cast as Penny for The Big Bang TheoryCanadian actress Amanda Walsh played the female lead—then named Katie—in the show’s original pilot. CBS initially rejected the project, but the network finally picked up the show when Cuoco joined the cast for the second pilot.

2. She dated The Big Bang Theory costar Johnny Galecki for almost two years—and was able to keep it a secret until after they broke up. She first publicly spoke of the relationship in an interview with CBS Watch Magazine, and revealed that they’ve been able to remain friends—despite the awkwardness of playing your real-life ex-boyfriend’s love interest on television. “At the wrap party he gave me a huge hug and I was like, ‘I’m really proud of us,’” Cuoco told the magazine in regards to their mature breakup. “And he was like, ‘I know, me too. We didn’t kill each other, or kill other people. We made it.’”

3. She played “little Ellen” to Ellen DeGeneres’ character on her hit show Ellen. When she was 11, Cuoco played a younger Ellen Morgan in a flashback at summer camp. Years later, DeGeneres welcomed Cuoco as a guest on her daytime talk show.

4. She snagged a Teen Choice Award for herself. In 2003, Cuoco won The Teen Choice Award for Choice TV Breakout Actress for her role in ABC’s hit comedy 8 Simple Rules. After the series’ star, John Ritter, passed away, Cuoco’s character Bridget initially felt guilty for the last words she spoke to her TV dad: “I hate you” (he didn’t allow her to borrow the car).  The show ran for two more seasons after Ritter’s death.

5. Cuoco is playing Rob Lowe’s wife in the upcoming TV movie: The Drew Peterson StoryCuoco will portray Stacy Peterson, Illinois’ police sergeant Drew Peterson’s fourth wife who went missing in 2007. Peterson is now in prison awaiting trial related to the mysterious death of his third wife in 2004. Kaley recently hinted to a crush on her attractive costar: on August 1 she tweeted, “Officially done playing @roblowe 's wife. Ah why can't this dream continue! #sodontwannawakeup.”

Watch Cuoco host the Teen Choice Awards on FOX, Sunday at 8 p.m. EST.