10 Behind-The-Scenes Facts About Knocked Up

After revolutionizing the 21st century film comedy by bringing a sweet, earnest sensibility to crude material and allowing his cast to improvise in The 40-Year-Old Virgin, Judd Apatow returned with a sophomore directorial effort that proved it wasn’t a fluke.

Knocked Up stars Seth Rogen and Katherine Heigl as Ben and Alison, two people who have a one-night stand that results in a pregnancy, and have to get to know each other and figure out their relationship while she’s pregnant with their child. It’s a funny, likable, surprisingly honest movie. Here are 10 Behind-The-Scenes Facts About Knocked Up.

The movie was loosely based on Leslie Mann’s pregnancy with Maude Apatow

According to Knocked Up’s DVD commentary, Judd Apatow based a lot of scenes on moments from his wife Leslie Mann’s pregnancy with their first daughter, Maude (who appears in the movie with her sister as Pete and Debbie’s kids).

Ben’s angry phone call with a series of doctors was based on a real-life phone call made by Apatow. Alison kicking Ben out of her car on the way to the clinic was based on a real-life incident in which Mann kicked Apatow out of her car. Alison takes a bath to calm down while going into labor because that’s what Mann did.

Anne Hathaway was originally cast as Alison

Anne Hathaway was initially cast to play Alison in Knocked Up, but she dropped out due to creative differences with director Judd Apatow. Before casting Katherine Heigl in the role, Apatow considered several other romcom mainstays, such as Renée Zellweger, Drew Barrymore, and Cameron Diaz, as well as Uma Thurman, Claire Danes, and Juliette Lewis, who all either turned it down or couldn’t meet the shooting schedule.

Christina Aguilera turned down the role so that she could focus on her musical endeavors. Michelle Pfeiffer, Jennifer Connelly, Sarah Jessica Parker, and Brooke Shields were all up for the part, but the producers deemed them too old.

According to the credits, the baby’s name is Stephanie

By the end of Knocked Up, Ben and Alison have emotionally matured and put their differences aside to make a relationship work and raise their baby together. Although we see the baby being born and driven home by Ben — driving incredibly slowly, as new parents always do — we don’t see them naming her.

According to the end credits, which feature a rolling slideshow of the cast’s baby pictures, the baby’s name is Stephanie. It would’ve been nice if we got to check back in with Ben, Alison, and Stephanie in Knocked Up’s sorta-sequel This is 40 to see how they’re doing now, but all we got was a passing reference to Ben giving Pete some edibles.

A lot of the guys’ dialogue was improvised

As with any Judd Apatow production, a lot of the dialogue in Knocked Up (particularly between Ben and his friends) was improvised by the actors on the set. All of Ben’s friends have the same first names as the actors playing them — Jason Segel, Jay Baruchel, Martin Starr, and Jonah Hill — which made it easier to improvise lines and get into the roles of their fictionalized selves.

Seth Rogen’s writing partner Evan Goldberg suggested the “Dirty Man Competition,” which Apatow incorporated into the script because he thought that Martin Starr’s growing beard would be a funny visual way to chart the nine months of Alison’s pregnancy for the audience.

Initially, in pre-production on Knocked Up, director Judd Apatow planned to go a little guerrilla with the birth scene and use footage of a real birth. However, this turned out to be legally impossible, because the child would need a work permit before the footage was shot and they couldn’t get a permit before they were born, so their birth couldn’t be filmed for a movie.

This was revealed to be the reason why Anne Hathaway turned down the role of Alison. She objected to Apatow’s choice to use footage of an actual birth (back when that was the plan).

This was Ken Jeong’s movie debut

When it came to casting the doctor who would deliver Alison’s baby, Judd Apatow wanted an Asian actor who had some real medical experience, so he cast Ken Jeong. At the time, Jeong was a qualified doctor doing stand-up comedy. He’d had a couple of small roles on TV shows like Entourage and The Office (you’ll spot him at Michael’s improv class in the Season 2 episode “Email Surveillance”), but Knocked Up was his movie debut.

He shot it on a vacation week and has since credited it as his “first big break.” Jeong would go on to become a comedy superstar with fan-favorite roles in Community and The Hangover trilogy.

In most countries, the movie isn’t called Knocked Up

Selling a Hollywood movie with a title like Knocked Up to a foreign audience can be tricky, because the term “knocked up” doesn’t mean anything anywhere outside America. In America, audiences would see a movie poster for Knocked Up and immediately assume it was a movie about a pregnancy.

But translated into another language and presented to audiences overseas, Knocked Up doesn’t make any sense. So, the film’s title is very different in other countries. In Russia, it’s called A Little Bit Pregnant. In Portugal, it’s called Bloody Bad Luck. In Italy, it’s called Very Pregnant. In Brazil, it’s called Slightly Pregnant.

Steven Spielberg thanked Judd Apatow for praising Munich in the film

When Ben and his friends are out at the nightclub where Ben meets Alison, they talk about Steven Spielberg’s historical drama Munich. They like it because “Jews kick ass” in it: “If any of us get laid tonight, it’s because of Eric Bana in Munich.”

The actors improvised the whole conversation, and around one third of that improvisation ended up in the movie. When Spielberg himself saw it, he called Judd Apatow to thank him for complimenting his movie in Knocked Up, and Apatow sent Spielberg the full, uncut improvisation. Apatow later cast Munich’s star Eric Bana in Funny People.

Bill Hader “looked too old” to play one of Ben’s friends

Originally, Bill Hader was slated to play one of Ben’s friends in Knocked Up, alongside Jason Segel, Jay Baruchel, Martin Starr, and Jonah Hill. However, he was removed from the group, because he “looked too old” to convincingly play a member of that group of twentysomethings.

Hader does appear in the film, as the editor of Alison’s show on the E! network. Funnily enough, Hader used to actually work as an editor at E!, and found it surreal to be shooting a movie role as a character who does his old job, just down the hallway from where he used to work. Some of his old co-workers were there, too.

Knocked Up could’ve been a sequel to The 40-Year-Old Virgin

Judd Apatow initially conceived Knocked Up as a sequel to The 40-Year-Old Virgin, or at least set in the same universe. The two films (and, indeed, all of Apatow’s movies) share a lot of the same actors — Seth Rogen, Paul Rudd, Leslie Mann, Jonah Hill. Even Steve Carell makes a cameo appearance (as himself), and the story wouldn’t need a lot of tweaks to follow on from The 40-Year-Old Virgin.

Rudd’s characters in the two movies are very different, but Rogen’s character from Knocked Up could’ve easily been the same pot-addled, sex-crazed slacker who worked with Andy and co. at Smart Tech.