7 actors who played real-life serial killers in TV and films

It can be a huge challenge playing a serial killer onscreen, but several actors have risen to the task and gotten into the mind of some of the most horrifying people in history.

Here are seven actors who played serial killers.

Charlize Theron played Aileen Wuornos.

One of the biggest moments of Charlize Theron’s career was when she played serial killer Aileen Wuornos in the 2003 movie, “Monster” – a role that ended up landing her an Oscar. Wuornos was a sex worker who ended up killing at least six men on Florida’s highways between 1989 and 1990, and she was convicted after her trial in 1992. In 2002, she was executed by lethal injection.

Playing Wuornos required Theron to undergo a physical transformation, including weight gain and false teeth. According to what Theron told the Telegraph, she also visited a friend of Wuornos to read letters that she had written to her to help her get into character, and called the role “by far the most challenging work I have ever done.”

Zac Efron played Ted Bundy.

The movie where Zac Efron portrays Ted Bundy, "Extremely Wicked, Shockingly Evil and Vile," hasn't hit theaters yet, but it's already getting a lot of buzz. After all, Bundy may have killed 100 or more women and is known for raping his victims and was a necrophiliac.

But as Efron told Entertainment Tonight, he didn't use much method acting to get inside Bundy's head - in fact, he said the role was "fun."

"It simply tells a story and sort of how the world was able to be charmed over by this guy who was notoriously evil and the vexing position that so many people were put in, the world was put in," he said. "It was fun to go and experiment in that realm of reality."

Steve Railsback played Charles Manson.

Thanks to his crimes, just about everyone knows who Charles Manson is - the cult leader whose followers ended up killing around 35 people, including actress Sharon Tate. Then, in 1976, Steve Railsback ended up portraying him in the TV movie "Helter Skelter," and he took the role very seriously, even spending periods of time in dark closets alone so he could try to understand what it might feel like to be in solitary confinement.

"I did a lot of things for Manson," he told TVStoreOnline. "I read the Helter Skelter book. I studied his speech. I watched him speak. I did that to look for any contradictions. I listened to his music."

Brian Dennehy played John Wayne Gacy.

One of the most notorious killers in history, John Wayne Gacy raped and killed at least 33 men before burying many of them under his house. And what made him even creepier? The fact that he often dressed as a clown for children's birthday parties and sometimes wore his clown costume when he killed his victims. A man like that can't be easy to portray, but Brian Dennehy took on the challenge in the 1992 movie, "To Catch a Killer."

"I remember playing John Wayne Gacy, serial killer, very sick, neurotic, screwed-up guy. You know what? There's a part of me there, too, and you explore that," he told CBS News in 2007.

Jeremy Renner played Jeffrey Dahmer.

Jeremy Renner took on the challenging role of killer Jeffrey Dahmer in the 2002 movie "Dahmer," which followed his life and murders. Dahmer raped, murdered, and dismembered 17 men and boys between the late '70s and early '90s, and was ultimately given 16 life sentences. However, the New York Times reported he was beaten to death in prison in 1994.

And as Renner told Parade in 2009, playing Dahmer actually took a toll on his personal life.

"After I did the film, playing a guy who was basically a monster, things started getting creepy," he said. "My cat was stolen. Then some girl bit me in a bar because I wasn't paying attention to her anymore and I had to go to the hospital. It kept me single for a while, that's for sure. Lot of people I wanted to date, but people I probably shouldn't date."

Kathy Bates played Madame LaLaurie.

As chilling is "American Horror Story" is, it gets even scary when you consider that some of the characters in the show are based on actual killers who existed in real life, and in the show's "Coven" season, that definitely applied. Kathy Bates played Madame LaLaurie, who tortured and killed at least four of the slaves she owned in New Orleans in the 1800s, according to Historic Mysteries.

According to Collider, playing LaLaurie was actually a positive experience, especially since working with Ryan Murphy helped her put her own twist on the show's version of this historical killer.

Richard Attenborough played John Reginald Christie.

John Reginald Christie was an English man who killed six women, including his wife, and was sentenced to death after he was found guilty in 1953 - ten years after his first murder, a 21-year-old girl named Ruth Fuerst, according to CBS. He also killed prostitutes and a baby named Geraldine and her pregnant mother, who he promised to help get a safe abortion. In the 1971 movie "10 Rillington Place," Richard Attenborough took on the role of Christie.

In a 1970 interview, Attenborough spoke of his hesitation to play Christie, noting that once he saw the script, he knew it was a role he had to take. "I do not like playing the part, but I accepted it at once without seeing the script," he told Games Radar. "I have never felt so totally involved in any part as this. It is a most devastating statement on capital punishment."