The "Knocked Up" cast is filled with familiar faces. Many actors have become a Judd Apatow staple, while others have appeared in countless film and television roles. Here is a look at the cast of 2007's "Knocked Up."

  1. Seth Rogen. Previously cast as the sarcastic friend with great one-liners, Rogen scored the leading man role in "Knocked Up" as a 23-year old slacker who managed to bed the beautiful Katherine Heigl. Rogen has been a regular cast member for writer/director Judd Apatow since the criminally canceled 1999 show, "Freaks and Geeks." Hilarious and scruffy, with a voice that is reminiscent of a Jim Henson creation, Seth Rogen proves that the most unlikely leading man, can also be the most charming, especially in "Knocked Up."

  2. Katherine Heigl. The lovely and talented Heigl may seem like an unlikely counterpart to Seth Rogen, but the chemistry works. After a string of unappreciated classics ("My Father the Hero," "Bride of Chucky") and three seasons on the beloved WB/UPN show, "Roswell," Heigl hit it big with "Grey's Anatomy." Although she had plenty of film experience, it was her role as Allison Scott in "Knocked Up" that finally gave her the title movie star.

  3. Paul Rudd. At the beginning of Rudd's career, he appeared to be a sweet and lovable every-man that women could fall in love with. After appearing in films like "Wet Hot American Summer" and "Anchorman," America was a able to see just how absolutely hilarious the guy is. With plenty of whip-smart script in Apatow films, Rudd is able to use his obvious intelligence to heighten the dialogue.

  4. Leslie Mann. Before "Knocked Up," many movie-goers remember Mann best for her role as Jon Stewart's fiance in 1999's "Big Daddy." Mann has a way with holding her own in an argument, whether it be with Adam Sandler or her tortured husband, Pete (Rudd). As Allison's anal and overly anxious sister, Debbie, Mann brings a whole new level of crazy to the table. Her spastic and energetic character is a perfect counterpart for the mello Paul Rudd. Many directors that hire their wives for films don't have the added bonus of casting a pitch performance, which is exactly what Apatow got from his wife, Leslie Mann.

  5. Jonah Hill. Slightly offensive, but funny nonetheless, Hill delivers the most obnoxious character among Rogen's ensemble of friends. With a cameo role in "The 40-Year Old Virgin" (he was the kid who wanted to buy the goldfish platforms), it was apparent that he was another actor that needed more screen time. Although, he may never have the same appeal that snagged Seth Rogen a starring role opposite a super hot girl, Hill is a welcome addition to any comedy cast.

  6. Jason Segel. Another "Freaks and Geeks" alum that manages to light up the screen with his awkward stature and goofy smile. After appearing in Judd Apatow's follow-up FOX show, "Undeclared," Segel took an Apatow sabbatical before playing, who else, Jason. With a starring role on "How I met Your Mother," and writing and starring in the box office smash, "Forgetting Sarah Marshall," Jason joins fellow "Freaks," Seth Rogen and James Franco in a very successful career.

- Megan Bushree