All your favourite MasterChef contestants from seasons past, return to the MasterChef kitchen for the first ever MasterChef All Stars.

Tonight there is $20,000 up for grabs for our contestants' charities, so it's game on! Competing in four heats, our All Stars must first cook a Lebanese dish. Who will take home the $5,000 heat prize?

Everyone loves a sausage sizzle, so the All Stars head to Fire and Rescue NSW State Training College to treat 100 trainees. This isn't going to be an ordinary sausage sizzle.

It's the first Mystery Box, and what a Mystery Box it is. Some of our most impressive guest chefs from the past three seasons have included one ingredient each in the box.

A true All Star must have their knife skills down pat, so Gary puts our 12 contestants to the test with an onion chop challenge. Who will win their team an advantage?

With $10,000 up for grabs for their charity, the All Stars must conquer their "nightmare" dish to take home the prize.

Paired with one of Australia's best chefs, the All Stars must cook-off against their top chef for the chance to gain immunity and avoid tomorrow night's pressure test.

An old classic, the Beef Wellington is a complex dish with a number of pressure points, but it must be cooked perfectly if the All Stars are to avoid elimination.

The 10 All Stars have come a long way since they first stepped into the MasterChef kitchen. Now it's time to show the judges just how far they have come with the "Where are they Now?" cook-off.

The nine contestants play the ultimate game of chicken! There's no time to be complacent, it's time to get creative. Expect chili popcorn chicken, chicken ballotine and more tasty treats.

The contestants are challenged to bake one of eight different cakes using recipes created by the Country Women's Association. The All Stars need to be at the top of their game if they are to win.

Revenge is a dish best served hot! The All Stars strike a match to the mystery box, using it as fuel to cook their dish. Who will head home at the end of the challenge?

Who's got a sweet tooth? The All Stars arrive at the MasterChef kitchen, greeted by judge George, who declares they must recreate a mouth-watering chocolate dessert based on the Greek god, Zeus.

Special guest chef Curtis Stone joins the top five all stars in the MasterChef kitchen for tonight's challenge. Curtis sets the task? they must cook a lobster ravioli with no time limit and no recipe.

After sourcing ingredients for tonight's challenge at Sydney Fish Markets, the top four All Stars are greeted by 100 Navy heroes. They learn they must cook lunch and be judged by the Navy heroes.

The winner of last night's Navy challenge has immunity and has headed straight into the grand finale, leaving the remaining three to battle it out for the final two spots.

The first MasterClass of the season welcomes all the All Stars back to the kitchen for a fun 'battle royale' with Gary and George. It's a team mystery box full of Matt Preston's favourites.

The three All Star finalists arrive at the MasterChef kitchen for the last time, fired up and ready to fight it out for the title of MasterChef All Star and $25,000 for their charity.