PIZZA Hut may be turning 60 this year - but it hasn't forgotten its roots.

The fast food chain is celebrating its massive milestone in Australia with a national giveaway of 18,000 free pizzas today and tomorrow, featuring one of its most popular toppings to date.

60 large Pan Super Supreme pizzas will be given away across all of their 292 stores, and the first 30 people to line up from midday will get one free.

In conjunction with the national giveaway, it is also walking down memory lane to look back at how Pizza Hut has changed.

Pizza Hut's Head of Corporate Affairs Joanne Moss told News Corp Australia that they are considering bringing back some of their menu items that have the chain's "heritage" attached to them.

"Never say never, we know our customers have a fondness for the older stuff," she said.

"It just depends on the demand and love from consumers. That nostalgia makes us one of the most recognised brands in Australia."

HOW IT ALL BEGAN

Pizza Hut was first started by two Wichita State University students, brothers Dan and Frank Carney in 1958.

With $600, they named their restaurant Pizza Hut and in a decade, it grew to 310 restaurants, with more than a thousand by 1972.

Their original restaurant still stands today on the university campus and has been turned into a museum where fans can come and look at incredible memorabilia from the store.

The original logo featured a cartoon character known as Pizza Pete. He featured heavily across the restaurants' signage and on its menus.

By 1976, Pizza Hut had more than 2000 stores including 100 international stores in England, Japan and Australia. The first store was in the Sydney suburb of Belfield in 1970.

Today, Pizza Hut has around 13,000 restaurants in 130 countries.

AUSTRALIA'S PIZZA HUT GROWTH

In Australia, Ms Moss told News Corp that Pizza Hut still has a limited number of "red roof" restaurants operating Ballarat, Shepparton and Bendigo in Victoria, Browns Plains, Gympie, Toowoomba, Willows and Kirra in Queensland, Lake Haven, Minto, Orange and Windsor in NSW, Marion in South Australia and New Town in Tasmania.

Archived photographs reveal the old restaurant logo and vast scale of the once beloved Pizza Hut restaurants across the country.

But by 1985, they began to look at a new delivery model, and Ms Moss said they started to create "takeaway kiosk" stores to meet the need for customers looking for more convenience.

"We then looked at the casual dining experience that guests wanted, and we created 50 restaurants that allow guests to not just order and pick up, but come in and dine," Ms Moss said.

"We have these more modern dine-in restaurants in places like Coolalinga in the Northern Territory, Waterloo and Marsden Park in Sydney.

"The Pizza Hut at Marsden Park for example has a jukebox and popcorn machine in it as a flashback to the past."

Then later created Pizza Hut's express stores to fit into shopping centres.

PIZZA HUT'S INNOVATIVE MENU

For diehard fans who loved to dine in, Pizza Hut was most well known for The Works which began in the 1980s - an all you can eat dining experience that featured pizzas, salads and a dessert bar.

Ms Moss said they were the first fast food chain to invent the famous Bigfoot Pizza that went global.

They also created the Stuffed Crust Pizza, that was also sold worldwide.

The crust was filled with cheese, and later, they experimented with other fillings like the Hot Dog Stuffed Crust, the Cheeseburger Crust and the Vegemite Pizza also had its own stuffed crust.

Of all the toppings they have ever sold, Ms Moss said that the most popular toppings to date include the Super Supreme, Hawaiian, Pepperoni Lovers and BBQ Meatlovers.

FAMOUS PIZZA HUT AD CAMPAIGNS

Pizza Hut has had many iconic TV ad campaigns in the 1980s and 1990s. Among them was a group of hospital patients singing for their Pizza Hut meal from their hospital beds that starred Hey Dad! actor Ben Oxenbould.

Another involved the character of 'Dougie', the Pizza Hut delivery boy played by Australian actor Diarmid Heidenreich.

Heidenreich also did ads alongside Tim Shaw when he was doing commercials for Demtel products, and former Melrose Place star Andrew Shue, who played Billy.

Heidenreich ended up losing the gig and served 77 weekends of periodic detention in Parramatta Jail for a drug and alcohol-fuelled car smash that left a girlfriend in hospital back in 1996.

But he later went on to a steady career in TV where he had roles in shows including Home And Away, Water Rats, McLeod's Daughters, Underbelly and Packed to the Rafters.

Just last year, they ran a Pizza Hut in July campaign where they promoted a new topping of Smoky Ham Hawaiian for a limited time.

A MORE MODERN LOOK FOR STAFF

The Pizza Hut of today is looking for a more "broad appeal", Ms Moss said that they want to meet the needs of customers including millenials who are interested in the brand, and families who are looking for something wholesome and quick. They are also keen to look after their "diehard fans" who have been dining with them from 20-30 years ago.

Aside from the restaurants and menus changing, staff uniforms also had a makeover.

These days, staff have ditched the red and whitre checked shirt in favour of a blue denim-coloured shirt at their casual dining eateries.

Ms Moss said Pizza Hut still has staff that have been with the chain for decades.

"We have employees that have been with the brand for decades - we have a strong culture of promoting from within and have many employees that started as kitchen hands/drivers and are now senior managers," she said.