Carrie has been on the panel show before so knew what to expect, but admits her fingers were crossed that the other panellists didn't ask her about politics.

"I would've had to plead ignorance," she says. "I'm interested in all that, but I've just had a baby, I've not been paying attention."

Her son, Isaiah, was born in February, slap bang in the middle of Underwood writing Storyteller, her fifth album, which is released this month.

"I wrote a lot and recorded a round of songs before I was heavily pregnant, but there wasn't a whole lot I could do towards the end, so I wrote a whole lot more," says the 32-year-old, adding that there's no difference between those penned pre and post-baby.

"I'm just as angry as I was," she jokes, in reference to some of her more angsty songs like Before He Cheats, all about getting her revenge in before finding out her no-good partner's been dancing with some "bleach-blonde tramp" who can't shoot her whiskey.

She took three months off after Isaiah was born, and s ays she's not really changed since becoming a mother - though she doesn't have time to watch TV any more, goes to the supermarket late at night when the baby's in bed and has finally learned to delegate.

"It's harder to focus, but the team around me have definitely picked up some slack and made things much easier.

"Take photos: normally I'd go through every single one from a shoot, but now I'll say, 'Just pick your favourites', and I'll OK it from there. You really have to learn how to multitask and work smarter. But I get more done. Having a baby has made my crazy life even crazier."

In 2005, Underwood won the fourth series of American Idol. As the short video before her first audition in front of Simon Cowell, Randy Jackson and Paula Abdul showed, she grew up on a farm in Oklahoma, and dreamed of travelling out of her home state, let alone to another country.

She wowed them with her pure, country voice, and it never really looked like she wasn't going to win.

Since then, Underwood's become not just the series' most successful ever contestant, but one of the biggest-selling artists in the States full stop, having sold close to 65m albums. The vast majority of those sales come from the US, however - her debut Some Hearts, for example, shifted nine million copies, 7.4m of them in America.

Fourth album Blown Away, however, reached number 11 in the UK, a considerable improvement on previous album Play On, the only other one to chart here, which reached 93. Don't be surprised if Storyteller goes to the top of the charts, though.

"I feel like it grows and grows and grows in Britain," she says. "There are opportunities to go to new places all the time as well, so it grows everywhere. I don't want to force anything too much, but still want to give it a shot."

She says country music has been getting more and more popular in the UK since she first started releasing music, a time when she would be told in meetings by "the suits" that there was no point bothering with Britain.

"'Brits don't like country music', they'd say, and that would be that. But that's not true now, if it ever was, and I think country music doesn't hold true to a lot of the stereotypes that used to go around. I'm not a trucker, for a start.

"People think of cowboy hats and boots, or Garth Brooks, or singing about your momma while you're in prison or whatever," she continues, "but there's so much more to it than that."

She thinks the TV show Nashville, which stars Hayden Panettiere as country sensation Juliette Barnes, might have something to do with it, along with Taylor Swift, iTunes making it easy for fans to find more of the music they like, and social media.

"I think it's going to be interesting to see what happens, but it's nice to think that other people are into it too, outside America. That's the great thing about social media, when you see, 'Hello from Brazil', or something, I realise how far it's spread already."

Fifth time around, Underwood says she wanted to change things up slightly, to stop things getting stale.

New producers and writers were brought in, and she's even tried a love song or two for the first time.

"I don't like love songs," she says. "Whether to listen to or perform. They're hooey. Like romantic films, they're just not believable and they're not how people talk."

She found the right songs, however, which went some way to changing her stance.

"I'll Never Love You Again was a conversation between two real people and it felt believable to me, so I recorded it."

Underwood's currently planning a tour, although she says she has "no imagination at all" for staging a show, but has requested there are as few bells and whistles as possible, and will be back in the UK later this year for more promotion.

Until then, she'll be back in Nashville, busying herself with looking after Isaiah and supporting her husband Mike Fisher, centre for the Nashville Predators ice hockey team.

"The season is starting, so we have to juggle work now," she says. "I'm from Oklahoma, there's not much ice there, but in Nashville, it's a big thing and I've become a fan. I don't worry about him playing, he's built like a fridge and although he does fight, I don't think I've ever seen him lose.

"In Nashville, everyone just shows up and wants to have fun," Underwood adds. "We want the team to win, of course, but it's mainly about the chants, the nachos and the beer."

EXTRA TIME - CARRIE UNDERWOOD

:: Carrie Underwood was born in Muskogee, Oklahoma on March 10, 1983.

:: In 1996, it looked as if she was about to be signed to US company Capitol Records, but the deal fell through after a change of staff of the label. She says now she believes it was for the best.

:: During American Idol, after singing Alone by Heart, Simon Cowell predicted Underwood would win the competition and go on to outsell previous American Idol winners. He was right.

:: Since winning the show, she's earned more than 100m US dollars from album sales and touring.

:: She's a big fan of TV series Nashville and The Walking Dead, admitting she'd like to play a zombie in the latter.

:: Carrie Underwood releases fifth album Storyteller on Friday, October 23