For many, a bottle of champagne would be iced, but for Hayley, she opted for three consecutive sessions at Alcoholics Anonymous.
"I was initially quite calm after hearing I'd got the job, but then about three days later, I was just sitting there and I had this sudden feeling of excitement, but it was mixed with terror," she confesses.
"So I went to AA three times that week, just going to keep myself very sane."
It's been three years and three months of sobriety for Hayley, 37, who quit alcohol and sought professional help when her drinking spiralled out of control in her early 30s.
Previously, she's casually brushed aside her abstinence as party-girl-gone-good. But as she speaks to Woman's Day, Hayley explains that her recovery has been a lengthy process and one she still battles with today.
"I was never a very controlled drunk," she admits. "I wasn't drinking every day, but when I started, I was like Frank the Tank [from the movie Old School]. It just came to a point where I was doing it too much and I was sick.
"I couldn't go out and just have two. This was my 30s and it wasn't stopping. I didn't think I was going to grow out of it naturally."
So in 2014, at the age of 33, the former professional ballroom dancer checked into her first AA session.
It was the start of a new life that didn't involve hangovers and regret.
But even today, Hayley admits that she has to keep an eye on her "sanity", explaining that her three-day check-in after landing the job of her dreams was to ensure she didn't undo the hard work she's put in.
"The further you go, you don't feel like having a drink," she explains.
"I look at alcohol and I feel a bit sick. I can feel the poison in it. But you have the brain still, so you go to AA for free counselling and it keeps you sane."
In the past three years, Hayley has had quite the phoenix-like evolution from the good-time blonde who was once pulled off air when More FM breakfast bosses realised she was still under the influence of alcohol – just two days after she failed a drug test on live radio.
Last year, she headed back to the University of Auckland to complete the history degree she started in her 20s, while also adding a politics major.
And as she studied, a new passion was ignited. Hayley took an active role in the Green Party, running as candidate for the 2017 general election in Helensville, which was once the former seat of John Key. She also went on to co-host the political show Back Benches for Prime.
It couldn't be further from her days of glitter and glam as a professional dancer on New Zealand's Dancing with the Stars and the UK version Strictly Come Dancing.
If all had gone to plan, Hayley would have completed her studies this year and started to prepare for her second attempt at an electoral takeover in 2020.
But then TVNZ came calling after watching her burgeoning presenting work on the likes of Best Bits and sports show The Crowd Goes Wild. And her degree and political career have now been justifiably shelved.
"I didn't expect it – and getting the job has been a complete surprise," she smiles. "It's hard to say what is going to happen in 10 years, but in my head now, I would think, yes, I will go back into politics."
This has been a somewhat contentious issue for critics, who believe that Hayley is going to struggle with the move from having a political agenda to unbiased breakfast show journalist.
"I was just reading Twitter and I was cracking up," she says. "I've been called a communist on there, which is just hilarious. But I'm going to do my best not to read it. I know not everyone is going to like me and I just have to avoid the trolls."
It's not the first time that the TV host has faced online criticism. In 2014, Mark Richardson, her co-host on The Crowd Goes Wild, called her the show's "blonde bird".
Unsurprisingly, Mark's comment became a hot topic on Twitter, with Hayley admitting that she and her mum went through each of the tweets – good and bad – about her.
"But it didn't piss me off because it gives me more fuel to go out there and do things just as well as the men," she explains. "I feel people underestimate me, but I take that as a strength because they don't expect too much of me and then I can surprise them."
There's no doubt about it, Hayley might be a self-confessed tomboy – she admits she actually prefers snowboarding to ballroom dancing – but she's a girl's girl at heart.
It's an attitude she credits to her down-to-earth family. Her parents, Robin and Murray, have always told her she could do anything a man could do, and she grew up on an equal playing field to her older brother Logan and three male cousins It's perhaps no surprise that she finds the current climate, following the Harvey Weinstein crimes, an exciting time for women in entertainment.
"It feels like a real shift towards us seriously and honestly finally listening to women properly," she explains.
"But I have always had that in my family life. Dad listened to Mum, Mum listened to Dad and no-one was boss. That's hard to get in a relationship, but maybe we will get that now as women are powerful."
When it comes to the mention of romance, Hayley rolls her eyes and offers a slightly fed-up laugh. She's ready, but it's still a case of frogs rather than princes and she currently lives with two girlfriends from her school days out in West Auckland's Glen Eden.
"It's so difficult not drinking and dating," she confesses.
"It's something that I've had to practise. It took me six months to even kiss someone when sober.
"I didn't know how to flirt. I didn't know how to even get in the position to kiss them. But now after three years, the confidence is there."
And Hayley – who once famously dated former All Blacks captain Richie McCaw – has a back-up plan if she doesn't find Mr Right, admitting that she is more than happy to have a baby by herself.
"I've been clucky for about 10 years," says Hayley.
"I just don't want to do it with the wrong person. But having a baby by myself is an option as I get older."
But at the moment, the focus is on proving herself as a competent host on breakfast TV. Hayley reveals that as she gains experience, her number-one interviewee of choice would be politician Winston Peters.
"It's 15 hours of live TV a week and I will probably put my foot in my mouth," she laughs.
"Hopefully, it doesn't happen in the first couple of weeks. But if I look at where I was three years ago, I'm a completely different person. Becoming sober was a turning point and now I have this incredible job."