When the first series of Big Brother aired in 2000, it was an exciting TV moment.

A bunch of "real" people, stuck in a house, no interaction with the outside world, cameras on them 24/7. It was an addictive novelty.

But, over time, as ratings fell, the show grew predictable.

The contestants became cliches; the diva, the lad, the glamour girl, the camp one, the kookie one, and when Channel 4 dropped Big Brother a decade on, people assumed that was the end.

But Channel 5 bosses, who acquired the rights, disagreed. And they're promising that series 14, which starts this month, will be "harder and harsher".

It's called Big Brother: Secrets & Lies and Emma Willis is the new presenter.

Willis, 37, will already be a familiar face to many. A permanent presenter on The Hub segment on ITV's This Morning, she sometimes stands in for Holly Willoughby too.

She hosted the last two series of Channel 4's spin-off show Big Brother's Little Brother, then Channel 5's version, Big Brother's Bit On The Side.

But is she surprised there's still a thirst for the show?

"No. It was so brilliant from the beginning and it still is, even though it's very different to how it was – but it's still about the desire people have to be inquisitive and to watch, like we always watch soaps.

"Even those people who go, 'I'm not going to watch it this year' just need one fascinating character to get them hooked. We want to have a look behind that curtain and see what's happening in the house."

But she knows the old stunts won't cut it any more.

"You need more than a bunch of 20-year-olds who want to get drunk every night and have a snog," she adds.

Forget the contestants – all eyes are going to be on her, too.

It was announced in April that Willis would be taking over from Brian Dowling, and she says it was a "dream" offer.

"I would have been stupid to turn it down, and now I'm s***ting myself!" she confesses. "It's terrifying. I can't wait to get started but then another part of me is going, 'Oh no!'

And Willis knows she has big shoes to fill ... To lots of people, original host Davina McCall simply was Big Brother, and comparisons are inevitable.

"Davina will always be the queen, no-one will ever do it better than her. I think Brian stepped in really well considering he followed Davina. Now it's my turn and I don't want to be the one who drops the ball!"

Like McCall, Willis is a busy mum as well as a presenter.

She has a daughter, Isabelle, who turns four this month, and an 18-month-old son Ace Billy, with husband Matt, 30, a former band member of Busted.

So far, she's managing the work-life balance well.

"I'm really lucky. I work in the evenings when my children are in bed and I'm home when they're up," she says.

Becoming a mum has changed her priorities though.

"It changes everything. I think you stop sweating the small stuff and, I know it sounds really cheesy, but nothing really matters apart from them," she says.

Matt still does presenting jobs too (after winning series six of I'm A Celebrity... Get Me Out Of Here! he went on to present its spin-off show) and is currently rehearsing for musical The West End Men.

The couple, who married in 2008, try to avoid having overlapping contracts, and this has worked well so far. Making time for each other is a priority too – they try and have a date night "once a month if we can".

Sounds like Willis pretty much has it sorted. But it hasn't just landed on her plate.

"There was a point when I was going to pack it in," she says. "I wasn't working very much and thought maybe it wasn't for me. It's easy to give up, but I didn't."

Now, she has a supportive husband, two gorgeous kids – and, in her late 30s, a job that makes her feel like a teenager.

"Being given the responsibility of being in control of your favourite show is an amazing thing for me," says Willis. "I'm a massive fan and I get excited about the show, even though it's been going for 14 years."

big brother: secrets and lies, tomorrow, channel 5, 9pm