The hall of flame: Australian firefighters turn up the heat as they strip off and cuddle puppies and koalas for a racy new calendar shoot

It's the one time of the year firefighters enjoy things getting a little hot and steamy.

The 2018 Australian Firefighters calendar is sure to ignite the flames of passion in many with a crew of firemen posing shirtless alongside adorable animals.

This year's calendar is the 24th since the charitable project launched in 1993 and is packed full of bare chests, rock-hard abs and this time, koalas, puppies, wallabies and even wombats.

Shot in the iconic Steve Irwin Australia Zoo, the project features 12 months of brooding firemen in their fire-fighting gear while cuddling up with native wildlife.

Since its inception, pictures of the country's hottest firemen have raised over $2.3 million to charities across the country.

But to get a spot in the internationally renowned calendar shoot is not an easy feat.

The boys spend several months training and dedicated themselves to honing their flawless physiques for the chance to be picked as one of the 12 months.

And after being chosen the firemen are subjected to a 17-day gruelling photo shoot - the time it takes to snap a dozen perfect shirtless pictures.  

Three firemen who were lucky enough to land a spot on the 2018 shoot included Anthony, Dave and Jeff spoke with People in the US about their experiences at Australia Zoo and meeting Bindi Irwin.

'This year there was such a big difference being there at Australia Zoo,' Anthony said.

We stood right next to the vets and watched as they fixed a possum's broken leg.'

In 2018 there are six smoking hot calendars for enthusiasts to choose from.

Firefighters from NSW, Victoria and Queensland each feature in their own, while there is also a specific Hot Guy calendar - which includes images of firefighters from around the country posing solo.

The calendars can be purchased from here for only $20.