"This was where Toni had to, as the pregnant Loretta, dance an Irish jig for the evil Mrs Haggerty, who made her dance and dance and dance," Griffin said.
"The scene called for Loretta to get hot and sweaty and flushed, which wasn't hard because of the amount of dancing Toni had to do.
Because Loretta was pregnant, the costume department had bulked her up in the chest department with pink latex paddings that look a lot like raw chicken breasts.
"So, inevitably and wonderfully, the sweating and the jigging led to, in the middle of a take, both of the chicken fillets slipping from their desired residence to land with a plop, on the floor, at Toni's feet.
At which point she lost it totally and collapsed into hysterical laughter."
Griffin says Prebble (24), who has played the increasingly devious Loretta since the series first started in 2005, was "just right" for the role, although she first auditioned for the part of aspiring model Pascalle.
"She was clearly good, she clearly had talent, she had this kind of Christina Ricci look that suited the idea of the character of Loretta to a tee.
"Casting is, to my uncomplicated eyes, relatively straightforward - people either hit the character or they don't.
"We saw Toni do Pascalle and thought `Loretta'.
"We recalled her and we were right. Everyone who saw the tapes agreed."
It might be a departure to meet a young actor, or any actor, familiar with Plato, but not to anyone who knows Prebble.
As Griffin puts it, "Toni is a complete swot ... the Prebble over-achieving gene is strong in her".
"My family is totally academic," she agrees.
"My dad is a professor of tax law [at Victoria University], my mother teaches English as a second language [also at Victoria], my sister is doing her masters in law at Columbia University and my younger brother is in Dunedin, studying law and business."
Naturally, when Prebble finished school, at Queen Margaret College in Wellington in 2001, "university was always a given. It was valued in my family and also at the school - it was assumed that girls would go on to university and I wanted to".
Not content to go for one degree, Prebble aimed her sights at two: in law and arts.
She attended law classes for one year - attending 8am lectures so she could fit in her other job, presenting What Now for TV2.
But the Prebble law gene was dissipating.
"I appreciated law but it didn't stimulate me much."
However, the process of attaining the arts degree continues, with diversions into papers in English literature, psychology, philosophy, media studies, music - "just to try them out; they were all really fun".
She has just pulled out of an extramural third-year paper through Massey University.
Prebble's first taste for acting emerged at the age of 2, when she rushed on to the stage where her older sister, Rebecca, was performing in a school concert.
Later, when she was at primary school, her teachers told her to stop ad-libbing and "taking over the show" during a play.
She was offered her first professional acting job when she was 12, in the children's fantasy TV series Mirror Mirror 2.
She had just started high school - and if she took the part, she would have to leave school for six months.
"It was actually quite a hard decision for me to take that first part," she recalls.
"It was that situation where your dreams are suddenly coming true and quite full-on.
"I was at the netball trials and having a great time at school, I'd made all these new friends and we were just about to start rehearsals for the third-form musical, which was a big deal.
"I got called away from the trials and my mum told me I'd got the part - `You've got the weekend to decide if you want to do it.
"And if you do want to do it, you leave school next week'.
"That was a big decision. I knew my life was going to change pretty significantly.
"I think my parents were almost waiting for it to happen because I had been going on about being an actor my whole life."
Prebble's education continued via correspondence school - "My parents were on the phone quite a lot to [production company] the Gibson Group.
Their priority was that I got enough schooling but that I didn't get worked too hard".
She worked with William Shatner twice when she was 13, in William Shatner's Twist in the Tale.
"Funny, eh? It was in the trough of his career - post-Star Trek, before Boston Legal.
"He was pretty fabulous because of Star Trek. I remember him being quite nice."
In 1998, in her fourth form year, Prebble started working on The Tribe, a stint that lasted for five seasons.
She played Trudy, who became the Supreme Mother, different characters which were created for entirely pragmatic reasons.
"I was in the first series in my fourth form year in 1998 and at the end of that I decided to stop because that would have required another six months out of school and I didn't want to take any more time out," she says.
"Cloud 9 [the production company] were so supportive.
"They wrote the script around my school holiday dates - they were so nice. So I went to school as normal then worked in the holidays.
"But storywise they needed to invent a reason for all these comings and goings, so the Supreme Mother storyline was that I got kidnapped and brainwashed by this tribe called the Chosen - why are you laughing? This is serious stuff - who worshipped the dead father of my baby as a god.
"Then my tribe kidnapped me back and unbrainwashed me."
Prebble says being an actor on the telly while she was still at school was "never much of a big deal".
"It was just my job and none of the shows were particularly popular here, so I was never famous at all.
"I never experienced any jealousy or envy or people being mean to me about it.
"All credit to them for being nice girls but in my mind it wasn't anything great.
"I loved it but it was just my job. I think my friends at school felt sorry for me because I had to get up really early.
"I'd be at a party and it would be 10pm and I'd have to go because I was getting picked up at 5am.
"They'd go, `Poor you . . .'."
By 2004 the work was starting to dry up a little.
"I got a bit frightened, a bit worried about it," Prebble says.
"I was thinking, `Gosh, am I just going to be one of these child actors who does really well as a teenager then no-one ever hires them again?'."
No way.
The answer was Outrageous Fortune, for which she auditioned at the end of 2004.
She moved to Auckland the following year.
Because I ask her to, Prebble gleefully does the Loretta "look" that has become so familiar in the opening credits, her jaw lifted in defiance, her eyes steely.
She describes it as Loretta saying, "This is me, whatever. I'm pretty staunch - so look out!"Loretta, she says, has evolved from a gauche tomboy into someone "who uses her physicality in order to express herself . . . to manipulate someone, [get] another string to her bow".
Loretta has also had some pretty hot 'n' heavy sex scenes, which Prebble says are "kind of embarrassing to watch, knowing your parents are watching.
"That's definitely an issue".
The way she handles those scenes amuses James Griffin.
"The most interesting thing about Toni and the scripts is that she is a total prude, which makes it tough for her at times.
"But because we respect her so much we talk through all the Loretta bonking scenes thoroughly until we find stuff we are all happy to do.
"What she doesn't know is that her ideas for these scenes are actually dirtier than anything we would come up with."
Unlike some other young New Zealand actors, she has no immediate plans to move overseas in search of work.
"I've got so much more to learn here - I have only touched the surface of what I can learn from New Zealand and some of the practitioners here.
I don't have any finite plans because so much of an actor's career is unknown but I am pretty ambitious.
My dream is to have a career that keeps stepping up a notch.
"I would love to be in the position in a few years of working in New Zealand and internationally in theatre, film and TV.
"I'd love to have the opportunity to move overseas for a specific job as opposed to going over and starting from the beginning again."
• Outrageous Fortune screens on Tuesdays at 8.30pm on TV3.
