Pesto the giant fluffy penguin is growing up!

Pesto is beginning to lose his fluffy brown feathers in exchange for new waterproof ones

Do you remember Pesto the king penguin chick who reached stardom in September?

The penguin, who lives at Sea Life Melbourne Aquarium in Australia, went viral for his HUGE size - at just nine-months-old he was twice the size of his parents!

And now, Pesto is entering what keepers have called his "awkward teenage phase".

He is shedding some of his weight, and his brown fluffy chick feathers!

Who is Pesto?

Pesto will soon lose all his baby feathers to reveal his adult black and white waterproof coat

Pesto is a penguin who reached fame back in September at just nine-months-old.

He stood out amongst the sea of black and white penguins living at Sea Life Melbourne Aquarium in Australia because of his chocolate brown coloured feathers, and huge size.

He was born in January weighing 200g, but by the time he was nine-months-old he had reached 22.5kg - the biggest chick the aquarium had ever seen!

The chunky chick attracted lots of fans including popstar Katy Perry after he was shared on social media and news channels across the world.

Why is he loosing his brown feathers?

A penguin chick must grow new waterproof feathers before it can go out to sea in the wild, this is called fledging

Now Pesto is hitting the news again - as he makes his transition into adulthood.

Pesto has started to fledge.

This term means that the once fluffy brown penguin is losing his baby feathers and black and white waterproof adult feathers are taking their place.

Sealife Melbourne say "Fledging usually takes 3-4 weeks as the brown downy feathers are lost to reveal the adult king penguin feathers.

Pesto will lose most of his feathers over October and November."

Pesto used to have a full coat of fluffy brown feathers

Fledging means that Pesto's new feathers will be waterproof - meaning once he is fully fledged he can start to swim!

The fledging process can last up to six weeks.

“Don’t worry he’ll still be just as adorable, he’ll just be rocking his new tuxedo!” the aquarium said.