Jennifer Aniston's Dark Debut in 'Horrible Bosses'

July 6, 2011— -- Contrary to reports, Jennifer Aniston will not appear topless in her new movie "Horrible Bosses," but you will still see her like never before.

Aniston, who stars as a "sexually aggressive" dentist who harasses her male assistant in "Bosses," which opens Friday, recently set the record straight about all those topless rumors.

"I have idea where those rumors started, but it's a good rumor," Aniston told the Chicago Sun-Times earlier this week.

Rumors circulated in May that Aniston had filmed a scene in which she's naked above the waist. But the 42-year-old actress said no such scene was ever shot, nor will it surface in the DVD.

"Not true at all," she said with a giggle. "Where do these things start?"

Even the raciest scene, in which Aniston appears in an open medical jacket without a shirt or bra underneath, still leaves much to the imagination.

Make no mistake, though, "Bosses" will definitely show a darker side of Aniston -- starting with her hair.

The woman who made popular the "Rachel" hairstyle insisted upon covering her trademark streaky blonde tresses with a long brunette wig.

"We had this wonderful period of time I do call Hair Gate," Aniston told the Sun-Times. "The studio didn't want me to wear a wig. I was told, 'No one will know who you are.' I said, 'They will know my name from the credits.'

"I'm the one who insisted on the dark hair," she added. "I was doing a movie right before this and one after that had me looking more like me, and I knew this character had to be different."

Seeing herself in the mirror as a brunette, Aniston said, "I just felt such a freedom."

That freedom allowed the former girl-next-door Rachel Green from "Friends" to show a side of herself audiences haven't seen before.

In a trailer for the film, Aniston, stripped down to her underwear, seductively eats a Popsicle, a banana and a hot dog.

"There's a whole bunch of things she does that couldn't be put in this trailer. Stuff you won't believe," director Seth Gordon told Entertainment Weekly in May. "It's really exciting to see her do something a bit further … afield, if you will."

Her character, Dr. Julie Harris, sexually harasses her assistant played by Charlie Day. She sprays his private parts with water, talks dirty to him and suggests they have sex on a patient "put under" for dental surgery.

When he refuses, she threatens to tell his fiancee that they have been intimate in the past, holding up as proof compromising photos she had taken while he was under anesthetic during a dental procedure.

"I don't want to play it safe all the time," Aniston told the Sun-Times. "I wanted to take a risk.

"I wanted to do something that allowed me to go in a different direction. I've never had a script come to me in the past that allowed me to go in this direction," she said.

"The risk made it fun," she added.

Day, the target of her harassment in the film, said Aniston quickly wiped out any memories he had of sweet Rachel Green.

"She did bite my ear … really hard," Day told the Sun-Times.

"My natural reaction to what was coming out of her mouth was caught on film. My job was to act shocked at what she was saying. That was real shock."

Aniston also seems to be shocking her fans with her new boyfriend, the dark and scruffy Justin Theroux. Some tabloids labeled the actress a "homewrecker" for coming between Theroux and his live-in girlfriend of 14 years, costume designer Heidi Bivens.

"Either we're seeing another side of Jennifer for the first time or a brand new Jennifer," Popeater's Rob Shuter told ABCNews.com. "But she does seem to be changing up her life."