TORONTO - Jessica Pare says she had to endure three auditions before finally landing the role of Don Draper's secretary on the TV smash "Mad Men."

So when the Montreal-raised actress realized that the character only uttered one line of dialogue in her first episode, she wondered why she jumped through so many hoops to get the part.

"It turned into something bigger," Pare says with a laugh. "So I needn't have worried."

Indeed, Megan became a key figure in season 4 (out this week on DVD), playing an instrumental role in a surprise finale that polarized the show's diehard fans.

Developing the character was a challenge, says Pare, 28, because of the fierce code of secrecy followed by "Mad Men" writers, who keep viewers -- and actors -- in the dark about upcoming plot points.

Because of that, Pare says she didn't play Megan as though she had any ulterior motives in her relationship with Don (Jon Hamm), who was even more tormented than usual in season 4, as he grappled with the aftermath of divorce and the challenges of steering his upstart ad company.

"It was certainly a different kind of problem to play a full, thoughtful human being without making any decisions, necessarily, on where her character was coming from or was going, because I didn't have that information," says Pare, whose big-screen credits include "Lost and Delirious," "Hot Tub Time Machine" and the Canadian comedy "The Trotsky."

"I didn't want to play her as somebody who was using her relationship with Don to get ahead, or using her work to get to Don. I didn't want to pick any of those angles. I still don't really know where ('Mad Men' creator Matt Weiner) wants to go with it."

The square-jawed, immaculately groomed ad man had a rocky relationship with the office help in season 4.

One secretary quit after an ill-fated liaison with a drunken Don, and was subsequently replaced by crotchety Ida Blankenship, who promptly dropped dead at her desk.

The position was ultimately filled by the mysterious Megan, later revealed to have a French-Canadian background. Weiner seems to have given Pare the attribute as a result of her Quebec upbringing.

"The second episode I did, (Matt) remarked that I looked like a French movie star, and I said, well, I knew I had the French part down but the movie star thing was quite a nice compliment," Pare says with a modest laugh.

"So I think it captured his fancy that Megan might have a different heritage."

Because many of the walls at the fictional New York ad agency Sterling Cooper Draper Pryce are glass, Megan can frequently be seen sitting at her desk, even when she is not directly involved in a scene.

In keeping with Weiner's meticulous attention to the details of the "Mad Men" era, Pare says even the paperback stored in that desk was published in 1965, when season 4 is set.

"Everything on the set is period, so it was kind of fun to read this trashy romance novel," says the actress, whose father is a professor at McGill University.

But Megan did more than just peruse pulp fiction during season 4.

"Mad Men" writers gave the character some meaty scenes with her boss, who hit the bottle hard as he romanced a series of women and was devastated by the death of a key figure from his past.

Pare says Don's emotional turmoil stands in stark contrast to the personality of the actor who plays him.

"He's a really funny guy," she says of Hamm, who has showcased his comedic chops on "30 Rock" and "Saturday Night Live."

"That's kind of one of the interesting dichotomies of working on that show, because the camera's rolling and here's this very severe, kind of stern man who's cracking fart jokes as soon as they call 'cut."'

One of the key moments that cemented Megan and Don's relationship in season 4 occurred during their trip to California, when the executive's young daughter Sally (Kiernan Shipka) spilled a strawberry milkshake during an outing at a restaurant.

Used to the brittle and impatient parenting style of ex-wife Betty, Don was charmed when Megan lightly dismissed the mishap and calmly began to wipe up the mess.

Pare has high praise for Shipka, whose character became more prominent in season 4 as she coped with her parents' split.

"I often jokingly complained about working with (kids)," Pare says of her young co-stars. "The truth is these kids are far more professional and talented than I am."

Every member of that talented "Mad Men" cast has been put under an intense spotlight since the show premiered, and Pare is now experiencing that glare as well.

The actress says the show has allowed her to talk to some "really fascinating people who are at the top of their game professionally."

But despite the doors "Mad Men" has opened, Pare says she also intends to continue working in Canadian cinema (one of her first major film roles was "Stardom," the 2000 film from Quebec master Denys Arcand).

"I think I'd certainly gravitate to Canadian filmmaking, there's a different sensibility than there is in the States or in Europe ... I really want to keep working here," she says.

With new episodes of "Mad Men" months away (this week AMC announced that season 5 won't air until 2012), fans will have to get their fix by poring over the season 4 DVDs.

And they'll likely do just that.

Ardent viewers of the show have been known to watch episodes again and again, dissecting each nuance.

Their zealousness is something Pare has come to appreciate.

"It sounds like I'm sucking up, but the truth is that 'Mad Men' fans are an intelligent bunch of people," she says.

"I think that 'Mad Men' is a show that invites you to think about it and to watch again to sort of puzzle over the characters' motivations because we aren't necessarily let in on what's going on inside (their minds).

"The fans are a classy bunch."