'Superstar' Rachel Duffy is the most devious Traitor of them all - now even her husband can't tell if she's lying

She's the bubbly party girl who managed to bamboozle her fellow Traitors contestants with her extraordinary poker face.

And on Friday, ruthless Rachel Duffy – so keen to win that she got training from an ex FBI agent on the art of lying – was celebrating after being crowned the winner of the fourth series of the BBC show along with her fellow Traitor Stephen Libby.

In the most tense of finales, the pair were the first ever duo of traitors to triumph despite fans thinking that she would turn on her friend to win.

Stephen and Rachel have stuck together from the very beginning and managed to win the series together.

A selfless move from Stephen at the end, who could've snatched the entire prize pot knowing Jack Butler would vote Rachel.

But instead, both Stephen and Rachel were loyal to the pact they made at the family tree, which was to not betray each other.

The duo, who split the money and took home £47,875 each, was overcome with emotion telling how proud they are of each other. 

Rachel said: 'It is the best feeling in the world. I really thought it was such a big achievement to be the first female Traitor to make it to the final, then win.'

Speaking after his win, cyber security worker Stephen said: 'I can't believe I've just won The Traitors. 'm just a wee boy from the Isle of Lewis. This kind of stuff doesn't really happen to me.'

The duo then celebrated their victory with glasses of bubbly as they reflected on their unforgettable time on the show.

Speaking about Stephen and Rachel's alliance host Claudia Winkelman said: 'They were lovers in the turret and stuck together. They were totally Faithful to each other.'

At one point, the pressure almost got to Rachel, because when defending herself she accidentally said, 'If I was a Faithful.'

Fortunately for her, no one seemed to pay too much attention to the slip-up.

No expense was spared during the final episode, as the mission saw the five finalists trying to boost the prize pot by collecting cash in boats in a loch, before heading back to the castle in a helicopter.

Earlier in the night Jade Scott banished before the endgame.

But these certainly won't be the last winnings coming Rachel's way.

Industry insiders have told the Daily Mail that likeable Rachel's income is now set to rocket, as they tip the mother of three from Newry, Northern Ireland to become a millionaire – and the richest Traitor yet.

The communications director, 43, has been branded one of the BBC show's best-ever players, hailed for her ability to gain so many friends among the Faithfuls. And it's this appealing charisma which looks likely to turbocharge her earnings potential.

During the series, Rachel amassed an impressive 89,800 Instagram followers and a further 54,100 followers on TikTok.

Little wonder, then, that several celebrity agents known to this newspaper are preparing to swoop in to represent her.

On Friday, one told the Daily Mail: 'Rachel is a superstar, she's brilliant and she has been the standout contestant from start to finish.

'She has won millions and millions of fans and showbiz agents know they can make her a fortune. Already they are thinking about what other reality television programmes they can get her on. She has all of the ingredients for stardom.

'In a few days she will be inundated with people wanting to represent her. She has been a household name for the last three weeks and she will continue to be so.'

Rachel made no secret of the fact she wanted to win the show.

That aim was assisted by the four months of FBI online training she had endured, which, she said, enabled her to spot a liar at a hundred paces. The ex agent tutored her in how to spot micro-expressions, read blink patterns, and monitor breathing and swallowing.

She also practised keeping a straight face while lying to her lawyer husband, Seamus, and said she became so good even he couldn't now tell if she was telling fibs.

'My husband can't even tell if I'm telling the truth any more, not that I lie to him all that often, but I could wind him up and say something off the cuff, and he's like, 'I don't even know if that's true!' she said.

Rachel won't be the first Traitors contestant to develop a TV career: series three runner-up Mollie Pearce appeared on ITV's Dancing On Ice, while others such as Harry Clark and Diane Carson have made various television appearances.

Jonathan Shalit, founder of InterTalent, which looks after former Traitors winner Harry Clark, has said Rachel is the 'perfect commercial package' and brands will be lining up to work with her.

He told the Daily Mail: 'The Traitors isn't just a TV show any more. It's a star factory.

'Rachel is the perfect commercial package; intelligent, beautiful, calm, modern, witty, and sharp, but also warm and relatable. Brands don't just want popularity. They want noise.

'Right now, people are talking about Rachel. TV shows, podcasts, streamers, advertisers, and brands will all be lining up for her. Her age is also a huge advantage commercially because it aligns with real household spending power. She is absolutely on track to earn well into seven figures over the next year.'

Jonathan added: 'Traitors is now a worldwide franchise. Just look at Celebrity Traitors US with billboards across America, showing that Traitors can make UK stars like Maura Higgins, global stars.'

Her victory was a close call in the end, however: Rachel almost lost her place in the endgame as she and James Baker were both left at risk of banishment after a tie.

Claudia, 54, then announced the banishment would be 'in the hands of fate', as she brought out the chests of chance.

Each player chose a chest and opened them at the same time. Rachel had luck on her side as hers contained the shield, saving her to go on to win the competition.

One person who will be extremely proud is Rachel's beloved mother Anne who, she says, is the reason she put herself forward for Traitors.

She revealed on last Friday's show that she entered for the sake of Anne, 70, who has dementia and was diagnosed with Parkinson's when she was in her forties. She is a huge fan of the programme and, Rachel said, had clear advice for her daughter: 'not to get caught'.

In a poignant photograph seen on the show, Anne proudly holds up a T-shirt that says 'My daughter's a Traitor' on the front.

Rachel said: 'Mummy was just 47 when she was diagnosed with Parkinson's, four years older than I am now, and faces dementia, but still amazes me and my family every single day.'

She said that if she were to go all the way and win the money, she would spend it on Anne.

Rachel added: 'I just want to create memories with her while I'm still lucky enough to have her, and to create memories with my kids, because they just love their nanny.'

Rachel also lost her father, Raymond Mullen, in 2016 when he was 67. Her Facebook profile picture is a photograph of him walking her up the aisle on her wedding day. The pair were exceptionally close and she was devastated when he died.

All this heartache was her spur to victory. 'I will do anything to win. Nothing's off the table,' she said before filming started.

From the moment host Claudia tapped her on the shoulder, Mrs Duffy became a fan favourite.

She worked alongside fellow Traitors Stephen Libby and Hugo Lodge to murder and deceive the Faithfuls, but their plans were quickly thrown into chaos with a new twist: a fourth Secret Traitor.

Fiona Hughes was revealed behind the red cloak and soon went head-to-head with Mrs Duffy in one of the most memorable moments of the series. Faithful Harriet Tyce also tried to take Mrs Duffy down in dramatic scenes, but there was no stopping her.

When the cameras aren't rolling, Rachel is known as a fun-loving party animal, who enjoys karaoke, downing shots and dressing up. Her social media posts range from pictures of girls' trips away to Marbella to her doing a handstand in the ladies' toilets at a corporate awards ceremony.

As the head of marketing and communications at Clanrye Group – an organisation that works to support the local community in Newry with training and well-being services – she helps to plan overseas youth programmes and to manage family support programmes.

A friend of Rachel's told the Daily Mail: 'Rachel is the life and soul of any party. She gets on with everyone and just loves having a good time. She is not afraid of being the centre of attention. She takes the view that life is for living.'

On Friday, Rachel and her co-stars were watching the finale together before attending a boozy wrap party in central London.

She was cheered on at home by her four siblings, including her older brother, Darren Mullen, former manager of football club Newry City. She also has two other brothers, Neil and Shane, and a sister, Joanne. A family friend said: 'The Mullen family are all very well known in Newry.

'They are all very close and supportive of each other, so they hired a local venue to watch Rachel become a Traitor.

'She's got the backing of the whole of Newry. Everyone is behind her, although we don't know how she managed to keep it quiet for as long as she did. She'd told everyone she had to go to England for work!'

While spending time away from her family to film at Ardross Castle in the Scottish Highlands might have been difficult, it has certainly paid off.

There's little doubt that those sessions with the FBI were worth it.