There's a lot that fans don't know about 2003's How To Lose A Guy In 10 Days. This includes the fact that Kate Hudson improvised one of the movie's best scenes. In fact, a notable portion of Donald Petrie's uber-famous romantic comedy was improvised. And that just wouldn't have worked as well had the Almost Famous star and Mattehw McConaughey hadn't been cast.

While the movie wasn't exactly a smash hit when it was first released, it has subsequently gone down as one of the most beloved romantic comedies of all time and launched Matthew McConaughey's career. Of course, McConaughey ended up stepping away from the limelight to retool his rom-com image. The result was nothing short of astounding. But McConaughey knows that he wouldn't have had his dramatic resurgence had it not been for the foundation How To Lose A Guy In 10 Days gave him.

In an oral history of How To Lose A Guy In 10 Days by Vanity Fair, the cast and crew of revealed how Hudson really ended up playing Andie Anderson and how Matthew McConaughey found himself in the role of the hunky Benjamin Barry.

Is How To Lose A Guy In 10 Days Based On A Book?

How To Lose A Guy In 10 Days is roughly based on a novelty book written by Michele Alexander and Jeannie Long about their flawed dating techniques. The 1998 book, which director Donald Petrie called a "children's book", is quite small. So, a lot had to be added by screenwriters Kristen Buckley, Brian Regan, and Burr Steers.

how to lose a guy in 10 days Matthew McConaughey and Kate Hudson on set
Via: Instar

But the core of the book was what grabbed the attention of producers Christine Peters and Lynda Obst.

"What really drew me to it was this gender sense of humor—this perspective on how men expect women to behave and what women do that drive men out of their minds," Lynda Obst explained to Vanity Fair. "It seemed really juicy, so I began developing scripts"

How Kate Hudson Was Cast In How To Lose A Guy In 10 Days

Kate Hudson's crush-inducing role in Almost Famous is what ultimately set her up for being cast as the lead in How To Lose A Guy In 10 Days. She was just on that sort of career propulsion at the time. But, according to producer Lynda Obst's interview with Vanity Fair, Gwyneth Paltrow was also considered before there even was a script.

how to lose a guy in 10 days Kate Hudson young hot
Via: Vanity Fair

"Initially Gwyneth was attached to it, and then at some point, she must have had a conflict and had to pull out," writer Burr Steers explained to Vanity Fair.

Fortunately, Obst and former Paramount president Sherry Lansing were "madly in love" with Kate Hudson at the time. So while Gwyneth Paltrow didn't work out, the creative team was quick to attach the Almost Famous superstar.

Kate Hudson in a still from the movie How To Lose a Guy in 10 Days
 via YouTube, Boxoffice Movie Scenes channel

But despite her global fame and the fact that she came from Hollywood royalty, her castmates were wowed by her 'down to earth' energy.

"I remember Kate was so f***ing normal for a person that grew up in fame," Kathryn Hahn, who played Michelle, said to Vanity Fair.

Related: 'How To Lose A Guy In 10 Days' Had $14.2 Million Worth Of Jewels

"I was so moved by what family meant to her and how dearly her parents instilled that in her. She, Annie Parisse, and I became fast friends and made a lot of dumb trouble, smoking, hanging out, and just laughing all the fricking time," Hahn continued. "We, one late Friday night, were inspired to drive to Kate’s family’s lake house for the weekend. Kate asked me to put my bathing suit on and I came down and she said, 'Honey put on your suit,' and I said, 'This is my suit.' I don’t think she had seen a tankini before."

How Matthew McConaughey Was Cast In How To Lose A Guy In 10 Days

After Kate Hudson was hired as Andie Anderson, Paramount and the creative team went searching for her leading man.

"We were looking at guys and kept going back and forth about who would be the right guy," Kate Hudson said to Vanity Fair during the oral history of How To Lose A Guy In 10 Days. "The guy for me was really important. Matthew [McConaughey] came up in a meeting and I thought that was a great idea. I loved his energy. We immediately just got along."

How To Lose A Guy In Ten Days Kate Hudson And Matthew McConaughey carly simon you're so vain singing
Via: Youtube

Despite Kate Hudson claiming that she thought McConaughey was a "good idea", producer Lynda Obst told Vanity Fair that his casting process was a little more complicated...

Related: Here's How Kate Hudson Really Feels About Rom-Coms Today

"I’m on the phone with Jim Osborne, who was then at CAA, and he says, 'What about Matthew McConaughey?' I’m like, 'Well, Matthew McConaughey is so Texan, but it’s kind of genius.' So that’s in the back of my head," Obst explained. "Now we’re in the meeting and Sherry says to Kate, 'We have to bring this to a head. We have to find an actor that we both agree with, and I thought the test was terrific [with Matthew].'"

Andie and Ben
via Sky.com

Obst went on to say, "Everybody gave their positions. In order to break the impasse, I said, 'What about Matthew McConaughey?' And then Sherry [Lansing] said, 'Matthew McConaughey.' And Kate said, 'Matthew McConaughey.' And John Goldman said, 'Matthew McConaughey.' Everybody just looked at each other, and Kate said, 'I would do it with him.'"

Related: Here's What Michael Michele Has Been Up To Since 'How To Lose A Guy In 10 Days'

"I remember considering whether I was going to do it or not one night while on a walk down Sunset Boulevard," Matthew McConaughey explained to Vanity Fair.

"[Then] suddenly, this guy comes up out of nowhere to me—he was a fortune teller guru [and] goes, 'Can I tell you your fortune real quick?' I was like, 'Yeah, man. Sure.' He immediately goes, 'There’s a movie you’re considering right now. It’s a romantic comedy. You have to do this or it will be one of the biggest regrets of your life. It is going to be a blast, it is going to be an incredible experience and it is going to make a bunch of money.'"

Yeah, really... according to Matthew McConaughey, that actually happened...

"I remember thinking, 'Did the studio hire this guy?' I laughed at the thought, but I also remember taking a more serious consideration. I think I even accepted the offer the next day."