The show has averaged figures of 1.030 million from Monday to Friday, lifting to 1.052 million for live events and 1.083 million for nomination evenings. The opening show peaked at 2.392 million with a similar – or higher – figure expected for tonight's grand finale.

Nine first screened promos of Big Brother which pitched the show as being entirely different to anything seen before – it's amusing to think the promo even included footage of a priest and an older woman in a twin-set and pearls dancing among the so-called potential contestants.

What viewers got was the opposite: a bunch of young, mostly single people (including a secret millionaire) plus a talking fish called Surly and a housemate dog, Delilah. But it worked, and it worked very well.

The choice of host, Sonia Kruger, was perfect. She was lured from Seven by the promise of hosting Big Brother and she made the right choice. Kruger has been a standout as the anchor of the reality series, not too tacky, not too serious, just light and bright enough to have some fun. She has also managed to pull off a sometimes eyebrow-raising “futuristic” wardrobe with aplomb.

Aside from the usual antics and newfound suspense around secrets and nomination “superpowers”, Kruger and Nine's production team also handled a huge shock with tact and discretion.

When contestant Josh Moore had to leave the show after the death of his older brother Toby, the situation was treated with rightful sensitivity. The cameras were turned off as Josh was asked to leave the house to meet with his parents, who were there to give him the devastating news.

Josh also said private, distressing farewells to his housemates with the cameras off. He later returned for an on-camera farewell, to acknowledge his thousands of supporters, and will bravely make an appearance with all the other housemates during tonight's grand finale.

Although Josh Moore was tipped as an early favourite to win, since his exit from the show, the spotlight has landed on other potential winners, with earlier favourites Zoe and Michael exiting the show, to make way for the three remaining finalists: Ben, Layla and Estelle.

Benjamin, a 32-year-old from Victoria, works as an accounts manger but admitted his secret was he has always struggled to hold down a job. If he collects the $250,000 grand prize (plus a car, which is included in the prize) he won't need to worry about job applications for a whole.

Ben has styled himself as the measured psycho-analyst of the show, despite first being bitchy about some of the other contestants (particularly Estelle). He evolved into the person calmly discussing and confronting everyone's issues – and doling out his own brand of advice – to create better dialogue. It has clearly endeared him to many viewers.

As the only gay contestant on the show, he also has the vocal support of many in the gay community (plus plenty of straight supporters), who are pleased to see him as a role model and public face of someone happily in love with his male partner.

Layla, the 24-year-old English beautician who moved to Queensland in February, has perhaps been the most skilful of the lot: sweet and lovely but sometimes a little flustered and wide-eyed about the whole show. She has fluttered her eyelash extensions all the the way to the top, with a warm heart and a beautiful face. Her popularity didn't waver among fans despite having two separate romances in the house, with George the millionaire, then intruder Sam. With her much-loved hair-rollers and distinctive accent (she is the product of an English mum and Kiwi dad), Layla has the feel of a likeable character from an English soap. She even had a breakfast song created in her honour: “Oats a la Layla” which primary school kids are now randomly humming. It could be a winning combination.

Estelle, a 23-year-old from Victoria who works as a public servant but is studying law and turned up with an air of super-cool skateboarding chic –has turned out to be the surprising underdog in the show. She was widely disliked – and repeatedly nominated – by many of the housemates throughout the series, to the point where audiences started to wonder if she was getting a fair go. Her ability to avoid eviction is a sign of just how much support she has on the outside.

Now, with her trademark piece of lavender hanging from her hair, she as a legion of fans called the “Stella hood” and their voting power will be out in full force. Australia loves an underdog, so she has a real chance.

Out of the trio remaining, there seems to be a raw emotional connection to the experiences they have had in the Big Brother house. When they went to bed last night for the final time ahead of this evening's grand finale, they cried.

It is expected to be a very close call when the winner is announced tonight, early voting figures have revealed a margin of 1 per cent between all three contestants.

Up to 2.5 million Australians are expected to tune in for the grand finale. But even before the winner is announced, Nine has been celebrating the show's success.

In many ways, it was Surly the fish who epitomised the strengths of this year's show: funny, dry and surprisingly entertaining, he gave viewers plenty of laughs, which is often what escapist television is all about.

Surly also drily summed up the basic ridiculousness (and accepted formula) of Big Brother on last night's show, when Estelle asked him to name his highlight from across the series: “Watchin' you lot in the shower,” the fish said, without missing a beat.