SPOILER ALERT: This interview contains plot details of House of Cards' third season.

Image copyright Netflix Image caption Kevin Spacey won a Golden Globe for his portrayal of corrupt politician Francis Underwood

House of Cards writer Beau Willimon talks about the success of the drama, his "Cinderella moment" and counting President Obama as a fan.

If you're looking for plot revelations, you're not going to get them from House of Cards "show runner" and head writer Beau Willimon.

He's the man in charge of Netflix's award-winning political drama, which stars Kevin Spacey and Robin Wright as Francis 'Frank' Underwood and his steely wife Clare - a power couple who bring new meaning to the word ambitious.

Currently filming season four of the show, which was inspired by the 1990 BBC series of the same name, Willimon is skilled at keeping plot twists under wraps and is on a self-imposed verbal lockdown.

"I don't talk about upcoming seasons at all," he explains on the phone from the House of Cards set in Baltimore, Maryland.

"That's just always been my policy. We just tackle one season at a time."

Luckily for us, there was more than enough to talk about in season three, which began with Underwood installed as American president following the sudden resignation of the previous holder of the office.

Image copyright Getty Images Image caption Willimon made his screenwriting debut with political drama The Ides of March

So Beau, how do you make a character like Frank Underwood appealing to viewers?

The main thing about Francis and Clare is not their likeability, but their attractiveness. And I don't mean attractiveness in a sexual way, I mean in a magnetic way - you can't take your eyes off them.

Whether you condone their actions or not, and many of them should not be condoned, you are deeply invested in their success. [If you look at how] people are drawn to a character like Richard III, they feel like his co-conspirator.

He lets them in on what he's doing and a sort of intimacy forms with the audience, almost despite themselves. That's what we're going after with the Underwoods.

How do the pair come to terms with the reality of life in the White House?

We told the story of Francis and Clare's lust for power and what they were willing to do in order to obtain it. But I don't think anything can fully prepare you for the job of being President.

[Francis] is a man that not a single person cast a vote for. If we had him simply succeed at every turn, I think that would be a false story - they are human after all.

House of Cards was the first show to put all of its episodes up online at once. Did that change the TV industry?

Yes and no. The trend for binge-watching was at least a decade old, there just wasn't a term for it, so I think what Netflix did is respond to audience behaviour.

We don't advocate binge-watching - binge-watching's an option. Some people like to savour the experience; we just wanted to give people that choice.

Does that change the way you approach the writing?

No, because a good story is a good story - it has to be able to work both ways. We always assume that we've got a smart audience that have a good memory, that we don't have to repeat a lot and we don't have to infuse it with artificial cliff-hangers at every turn.

If the story's good enough, people are going to want to watch the next episode.

Image copyright Handout Image caption The third season of House of Cards saw the Underwoods in the White House

How much are Kevin Spacey and Robin Wright involved in the writing process?

I talk about the overall course of the season quite early on with them. We'll often sit down and talk about the script scene by scene.

They're a huge asset. They've been inhabiting these characters for years now, [so] there's things they understand that we will never have access to.

Sometimes the work happens on the day. We'll be rehearsing and I'll see or hear something that leads to a new idea, or they'll say "Maybe we don't need these lines - maybe we can act these as opposed to saying them." We're not precious about anything.

Is Kevin Spacey more involved in the show now he's left his role as director of the Old Vic theatre in London?

Kevin has a very rich and full life with his philanthropy, his dedication to the theatre, with his production company, but that never detracts from the show. That's top priority for him and that's been the case since day one.

Image copyright Getty Images Image caption Having George Clooney direct The Ides of March was a real "Cinderella moment", says Willimon

Pussy Riot make a cameo in season three at a dinner with the (fictional) Russian President. How much are you influenced by real-life politics?

We're not trying to rip from the headlines. That would be a fool's errand because we might be a year behind.

We're definitely influenced by the world around us. But at the time we were developing the storyline, Russia was not in the news. Then while we were shooting, Ukraine, Crimea happened - pure coincidence.

Do you think there are politicians watching the show who are getting ideas?

I don't know about getting ideas. I do know that a number of politicians watch the show, because they've come up to me in Washington. A lot of them are fans, some of them are not.

The President of the United States and the First Lady watch it. The President has tweeted about the show, so that's pretty mind-blowing.

Have any politicians asked for a cameo?

To date we have not done any cameos with real politicians. We do have real-life journalists and news personalities, but they're talking about things happening in our world. It's fun to see those folks and it adds a certain veneer of authenticity.

Image copyright Getty Images Image caption Executive producer David Fincher with Willimon, Wright, actress Kate Mara and Spacey

What difference has working on House of Cards made to your life?

It's the best thing that's ever happened to me. I've been very lucky. I wrote a play called Farragut North that became a film called the Ides of March, directed by George Clooney.

When I wrote that play I didn't have an agent, no one knew who I was. I sent it to 40 theatres around the country and all of them rejected it.

The play found its way into the hands of Clooney and I had that Cinderella moment where they said they wanted to make it into a movie. It had never even had a production at that point.

One of the doors it opened is House of Cards and for the past five years now this has been my life. I've had the opportunity to work with the very best people, I've learned how to become a show runner. It's been an incredible, thrilling experience.

Season three starts with the Underwoods renewing their wedding vows, but in the final episode they appear to split up. How much thought have you given to what will happen to them?

I didn't have it all perfectly mapped out. In terms of the split, that was more of a discovery - something I started thinking about midway between season two.

As we got talking about season three, we decided this is where the story needed to go - that we had actually unconsciously worked towards this in the first two seasons.

It became a terrifying and exciting thing for us to explore. And explore it we did.

House of Cards: Season Three is out now on DVD and Blu-ray.