The Sex and the City star was contacted by movie chiefs last month (Jan12) about tackling the part of Gloria Steinem in Lovelace after Demi Moore pulled out following her hospitalisation for exhaustion.
Parker was given the script to look through, but film executives needed her answer fast and the actress said yes before she could deliberate the implications of playing the feminist icon.
She tells Entertainment Tonight, "I read the script and didn't have enough time to think about it properly. (If I had), I probably would have said no, because it was a daunting experience for lots of obvious and less obvious reasons."
When the actress' namesake Sarah Jessica Parker was confirmed as Steinem in Lovelace, many news outlets suggested insiders who had preempted the casting announcement had simply mixed up the names - but the Weeds star admits she was the first person producers went to following embattled Moore's departure from the project last month (Jan12).
Her rep has explained that Mary Louise passed on the part because she already had a prior engagement, which conflicted with the film's Los Angeles shooting schedule.
According to the New York Daily News, the 47-year-old Big Apple resident was scheduled to serve as a parent chaperone on a recent classroom trip with her two kids - William, eight, and Caroline, five - and she didn't want to disappoint them by giving up her duty.
Moore dropped out of the project last month (Jan12) after she was hospitalised for exhaustion.
Parker is replacing Demi Moore as feminist icon Gloria Steinem in Lovelace, which also stars Noth - the actor who played her former onscreen lover, Mr. Big, in the hit TV series.
Noth insists he can't wait to re-team with Parker - and he hopes their characters will have a chance to interact.
He tells EOnline.com, "They should write us a scene. My character funds (1972 adult movie Deep Throat), so I should try to talk Gloria into a porn scene!
"It's a story chock-full of interesting characters. It's about the times that we lived in at the point (sic). It's about cutting through the myth. (Lovelace is) an enigma... It's an interesting look at what pornography was then and what it's become."
The actress had signed up to play feminist icon Gloria Steinem in the film opposite Amanda Seyfried in the title role, but she exited the project shortly after her hospitalisation last week (24Jan12).
After her emergency admission to hospital, Moore was taken to a medical facility to treat exhaustion and "improve her overall health".
The movie's producer, Heidi Jo Markel, has now revealed she was stunned to receive a phone call from Moore's representative explaining why the star had to drop out of the part.
She tells People.com, "It was a shock and concern for all of us. We got a call from (Moore's representative) on Tuesday morning and (the rep) said, 'There's been a personal crisis and we need to let you know that.' And we were clueless. We had no idea what it entailed. We just knew she was out, that there was probably a health concern, and to move on.
"It was mostly that we were worried about her health. Movies come and go, but someone's health is the most important. We just want her to be well."
However, Markel is pleased to have hired former Sex and the City star Sarah Jessica Parker as Moore's replacement, adding, "She's incredible. She has incredible moxie (courage) and strength of character and we were just so overjoyed that we could get her and she was interested in doing the part."
Earlier this week, insiders claimed Mary Louise Parker had landed the role of the feminist icon in Lovelace, but filmmakers Rob Epstein and Jeffrey Friedman have confirmed to Entertainment Weekly magazine they've signed the Sex & The City star up for the part.
Amanda Seyfried leads the cast as the X-rated actress-turned-anti-porn activist.
Moore dropped out of the film on Tuesday (24Jan12) after she was hospitalised on Monday night (23Jan12).
The actress has subsequently checked in and out of a treatment centre, seeking help for exhaustion and to "improve her overall health".
Sarah Jessica Parker will begin filming on Monday (30Jan12).
The actress was hospitalised on Monday night (23Jan12) after paramedics were called to her home and she subsequently checked into a treatment facility.
Her spokesperson revealed Moore, who has since left the specialist centre, had decided to pull out of Rob Epstein's film about notorious porn star Lovelace - and the director has wasted no time in finding a replacement.
Editors at Usmagazine.com claim Weeds star Parker has signed up to play feminist Gloria Steinem.
The actress will play a journalist in the biopic about porn star-turned-activist Linda Lovelace.
She joins Amanda Seyfried, who is portraying the title character in the film, Peter Sarsgaard, Hank Azaria, Adam Brody and Sharon Stone, among others.
The Hollywood Reporter has also confirmed James Franco will play Playboy boss Hugh Hefner in the film.
Moore, who was cast as feminist icon Gloria Steinem, pulled out of the project on Tuesday (24Jan12) after entering a treatment centre for exhaustion and to "improve her overall health".
The Ghost actress has entered a treatment facility following her hospitalisation on Monday night (23Jan12) when paramedics were called to her home.
A spokesperson for the star said, "Because of the stresses in her life right now, Demi has chosen to seek professional assistance to treat her exhaustion and improve her overall health. She looks forward to getting well and is grateful for the support of her family and friends."
Now her representative has reportedly confirmed to TMZ.com that Moore has pulled out of her upcoming role of feminist Gloria Steinem in director Rob Epstein's film about notorious porn star Lovelace to concentrate on her recovery.
Moore has appeared increasingly frail in recent months after noticeably losing weight following her split from husband Ashton Kutcher in November (11) after six years together.
The pretty blonde signed on as the porn star who became an anti-porn activist last year (11), and movie executive Patrick Muldoon reveals Seyfried is taking some big risks with the saucy role.
He tells Eonline.com, "It's very risque and there will be lots of nakedness in the movie, especially for Seyfried. It's a new thing for her."
But the producer insists his star won't be remembered for baring all in the film - fans will love her profound performance.
He adds, "She's doing such an amazing job. We're about two weeks into filming, and the movie's going to be incredible.
"Thematically, it's (movie) talking about how abusive the porn industry was to Linda Lovelace. Yes, there's a lot of nudity, but it's a message movie about respecting women."
The actress will appear alongside Peter Sarsgaard in the film, while Demi Moore recently signed on to portray feminist Gloria Steinem.
The moviemaker insists Moore was his first choice to play Steinem in the controversial film about the porn star who became an anti-porn activist.
He tells USA Today, "We wanted an icon to play an icon. So that led us to think of Demi and we got lucky. She agreed... (She was) very familiar with the story and we went from there."
And Epstein insists Moore bears a striking resemblance to Steinem: "It's a good hair match-up... Demi has the intelligence and the grace and warmth Gloria has. She'll bring that to the part."
He reveals Moore's role will be "small but pivotal" in the film, which will star Amanda Seyfried as Lovelace.
Steinem's representative has confirmed her client and Moore have "been in touch about the role".