Betty, supervillains and me: January Jones on life after Mad Men

Time is a funny thing – certainly when applied to an actor's career. I last met January Jones six years ago. The setting was a tranquil villa set far back from the hubbub of the Cannes Film Festival, where the actress had gamely arrived to promote The Three Burials of Melquiades Estrada, the directorial debut of her namesake, Tommy Lee Jones. That day, few were interested in speaking to this petite blonde from South Dakota, who was best known for a role in American Wedding, one of the legions of sequels in the American Pie series. But that was BMM – Before Mad Men.

These days, fans and press alike would trample Tommy Lee Jones, or most other actors for that matter, to get a glimpse. Such is the impact made by Jones – who turned 33 in January – that even the legendary Jack Nicholson was coaxed off the golf course to conduct a Q&A with her for Interview magazine. Jones, it transpires, had requested the actor to be her interrogator, after he had called her out of the blue to congratulate her on the first season of Mad Men, and told her she "shouldn't do too many interviews". Oh, the irony. Still, she enjoyed her time with Jack. "I don't feel like I'm getting trapped into saying something," she said, an indication of just how guarded she can be.

Playing Betty, the long-suffering wife to Jon Hamm's serial philanderer Don Draper, Jones has become part of more than just a popular television series about 1960s ad execs on Madison Avenue. Influencing everything from fashion to smoking habits, the show has become a full-blown phenomenon. "I think we all are very surprised," Jones tells me. "Not many of us thought that it would go past being a pilot, so it's been pretty cool to just see how it's evolved. It's been kind of a slow burn in terms of gaining different kinds of audiences. It's been really neat for us to not only have the critical acclaim, but have it become something that's a cultural phenomenon."

While Jones has a role in this summer's most-anticipated blockbuster, X-Men: First Class, she is aware that she can't judge her successes by box-office takings or ratings. "Success for me is to feel happy – 80 per cent of the time," she says. "That's been my goal in life. I think that comes from my father. He's a very optimistic, happy person. I'm not quite sure if I'll ever feel this, but I want to know how to be happy. I'm happy when at work. I'm happy when I'm with my family or my dog [a Yorkie poodle named Max]. But, you know, there's always that feeling of, I'm not satisfied. I have that thing in my stomach where I just need to keep striving for things. In my mind, I want the fairy tale."

As she reclines in her hotel suite, Jones seems troubled. Promotion makes her feel a little uncomfortable. There are pauses and a few sighs in that singsong voice of hers, and a pair of sunglasses to help keep her distance. In the past, she's admitted to lying in interviews to keep herself interested. "I do it because I'm bored of talking about myself or I have nothing left to say or I want to be private that day," she told one reporter. "I don't like living with other people and I don't mind being alone. I don't like having an entourage of people around me. I have a select group of friends who I hang out with. I just don't really have a lot of time or energy to put into a relationship when nothing's going to happen."

Not long after we meet she announces, via her publicist, that she is expecting her first child. "She's really looking forward to this new chapter in her life as a single mom," a "source" told People magazine, which broke the story. But Jones has not disclosed the father – and there's a good chance she never will. Having dated the multi-platinum singer songwriter Josh Groban for three years, she went on to enjoy a short relationship with Jason Sudeikis, star of US television institution Saturday Night Live (which Jones has guest-hosted). After their split in mid-January, Sudeikis was lost for words when a reporter later quizzed him over Jones's pregnancy – suggesting that even he didn't know.

I ask Jones whether she finds it hard to walk down the streets now. "Not really. I mean, here and there. I only notice it really in LA." Living in the Los Feliz borough, she's had to get used, since she started shooting Mad Men, to photographers lining the street waiting for her to emerge from her house. "I spent the whole fall and winter in London [filming X-Men] and didn't have any problem at all. But when people do come up, they're very respectful, so it's not a hindrance to my life at all. It's nothing I can't handle." So you haven't stopped going to the supermarket yet? "Not at all," she giggles. "If I can't go to the supermarket, that's not a good thing. I don't know if I would like that."

Certainly Jones seems to have bewitched her collaborators. "January is someone I think Alfred Hitchcock would've fallen in love with," says Liam Neeson, her co-star in recent thriller Unknown, in which Jones played Neeson's duplicitous wife. "She can portray that icy blonde... you never know what she's thinking." Her director on Unknown, Jaume Collet-Serra, concurs. "January is the Hitchcock Blonde, like Grace Kelly." Standing at 5ft 6in, with her svelte figure, sculpted blonde hair and piercing blue eyes, it's little wonder Jones draws these comparisons.

Much of this image, she insists, comes from the character of Betty Draper, rather than Jones herself. "I don't think the things that I choose to wear are very Grace Kelly," says the actress. "But when we first started talking about Betty, and delving into what her past may be, [Mad Men creator] Matthew Weiner and I, and Jamie Bryant, who does the costumes on the show, decided that Betty was a really big fan of Grace Kelly and tried to emulate her look. Whether it was through wardrobe or hair and make-up, I think that Betty tried to copy the covers of Vogue and Grace Kelly was a big star at the time."

Yet Jones has been guilty of perpetuating the Kelly comparisons. When Nicholson interviewed her, he touched on her aforementioned trip to Cannes. "It felt like I was in To Catch a Thief," she replied, presumably referring to feeling like Kelly and not Cary Grant. Still, the actress is not one to boast about her impact on the fashion world: when I put it to her that both she and Betty have become style icons, she stammers: "I guess the 1960s silhouette has come back a little bit in style, the waistline and the more feminine silhouette. But I don't know if she's a style icon for our generation – maybe bits and pieces of it. I don't know. As for me, I don't know if I'm a style icon!"

Until she was 10, Jones grew up in Hecla, South Dakota, a "very, very, very small" town with a population numbering just 400. Her father Marv was a gym teacher and high-school coach. Her mother Karen named her after January Wayne, a character in Jacqueline Susann's dime novel Once is Not Enough. Life was simple, but not unpleasant. "I had lots of friends, and with my sisters k [Jacey and Jina, both younger] and cousins, we'd all play. It was a very safe environment as well. We were outside all the time. There were no videogames. We had to use our imaginations – to come up with stuff to do." It sounds very wholesome. "Yeah," she says, dreamily. "Very much."

When her family moved to the nearby city of Sioux Falls for her high-school years, Jones had no ambitions to act. "I'm from such a small place, I don't think I ever harboured a dream of becoming an actress. I was always acting but I never thought, 'This is what I want to do.' I don't think I realised that it was a job at that point." She feels the same about modelling, which provided her escape route out of South Dakota when she was spotted by a scout at the age of 17. "I never thought I'd have a career out of it," she shrugs. "I graduated high-school early, and it was something fun to do. I'd never been anywhere but South Dakota really. So to go to New York, model... I don't know... sounded good at the time."

Her parents had insisted she wait until she finished high school before going to New York – and even then, the deal was that she'd come back after four months and go to college. The way Jones tells it, even she was in agreement at the time. "I never had any intention of doing it as a job forever. I was going to do it for a few months, then go to college, with the rest of my class." But while she obeyed her folks, she spent just two-and-a-half weeks back at home, never filled in that college application form and told her parents she was heading back to the Big Apple.

All they could afford was a one-way bus ride – a 37-hour journey – for their daughter. She bit their hands off. So what was it? The catwalks, the clothes? "Not so much the modelling aspect of it, but I did love the travel," she says. "And I loved being in the city, in New York, and meeting new people and seeing all kinds of things." Modelling for, among others, Abercrombie & Fitch, she says it also taught her self-awareness, independence and how to take rejection. Perfect, then, for joining the audition circuit – though Jones actually saw such cattle calls as a "cool, creative outlet" that made up for the fact that she never went to college.

It took her just two years to get to Los Angeles, completing that oh-so-clichéd journey from small-town Midwestern girl to Hollywood starlet. When she first arrived, she started dating another then little-known actor, Ashton Kutcher. They lasted for three years, during which time he reputedly told Jones she'd never make it as an actress – though she has since denied this. ("I never commented about him," she claimed recently.) By the time their relationship was over, Jones was proving any doubters wrong – well, sort of – by winning a near-silent but captivating part in the 2001 comedy-drama Bandits, alongside Cate Blanchett, Bruce Willis and Billy Bob Thornton.

Work has flowed "off and on" since, with a role in Richard Curtis's Love Actually and a part opposite her good friend Jack Nicholson in Anger Management keeping the bills paid. "Since I've been here [in LA], I've been lucky enough to work pretty steadily. But there's always downtime. It's just how you deal with it. I was never panicky about it. As an actor you just have to be patient and wait for cool things to come along and not just take anything that comes your way." Of course, when something like Mad Men comes your way, bringing you a regular pay-cheque and a profile money can't buy, it's easy to say that.

Only now are we beginning to see how Jones has reaped the benefits of Mad Men – not least with her casting in X-Men: First Class. A prequel to the X-Men trilogy of movies, which dealt with the rise of a group of mutant humans with superpowers, Jones plays Emma Frost. Known in the original Marvel Comics as the White Queen, she is able to turn her flesh into solid diamond. Oh, and she struts around in mini-skirts, kinky boots and a white fur hat. "In the comics, Emma Frost's wardrobe looks pretty painted on – very, very revealing and form-fitting," she says. "So we tried to emulate that without actually painting it on." Looking more like Emma Peel from The Avengers, Jones may finally shed the Grace Kelly image for good.

Far removed from the Betty Draper universe of domesticity and disappointment, Frost is a villain of sorts, hanging out with Sebastian Shaw (Kevin Bacon), the leader of a secret society named the Hellfire Club. The film is set in the same era as Mad Men, winding back to the time when the mutants' leader, Professor X (played here by James McAvoy) was only just discovering his powers, but, says Jones, "It doesn't feel as much like a period piece as Mad Men, because it's an action comic-book movie. [It meant] we had a little bit more leeway. Everything could look very badass – but still have a little 1960s flair to it. I hope the fans like it, because it's a very distinct look, to say the least."

Is she worried about what the fanboys might say about her casting? "Yeah, definitely," she nods. "I wasn't aware of who she was before I looked into the movie and did research into the comic. I know that she's iconic in the X-Men comics. So if you take something like that on, it's a big responsibility. You can't always please everyone, but hopefully the fans weren't too disappointed. They would've already spoken out if they were really bummed out, I think. The fanboys would have got on the phone and Warner Brothers would have said, 'OK, we won't cast her!'"

One of the "secret reasons" Jones took the job was that it meant she could hang out in London for several months, where filming took place. "It's my favourite city," she gushes. "I love London. It has a very interesting vibe that suits my personality very well." She stayed at the Covent Garden Hotel, went shopping with co-star Rose Byrne (who plays CIA agent Moira MacTaggert) and munched on Wagamama food. It caps a hugely hectic two years for Jones – season three of Mad Men was followed by stints in New Orleans (for the yet-to-be released Nicolas Cage movie The Hungry Rabbit Jumps) and Berlin (for Unknown) before shooting the most recent Mad Men series. "And I went from the last day of Mad Men, to a plane, to the first day of X-Men."

At least the show's fifth season won't hit screens until the spring of 2012, giving Jones a much-needed break, and time to adjust to the demands of motherhood (she's due in the autumn). As we part, I ask whether she can divulge any secrets about the forthcoming Mad Men plots. "Oh, the writers haven't even gone in the room yet, so no one knows," she blurts. Will Betty get even angrier at her troublesome daughter Sally? Her face falls and she looks sad. "Oh, I don't know. I hope not. It's not possible. Well, maybe it is. I don't know. We'll see." It's in that moment that I see a flash of the real Jones; not guarded or awkward, but one who cares for her character as if she's her best friend.

'X-Men: First Class' (12A) opens on Wednesday