See Pesto, the viral baby penguin, grow as he sheds brown feathers in new photos

Pesto is growing up!

After gaining fame in September, the king penguin chick begins shedding its brown feathers in exchange for new waterproof feathers as it transitions into adulthood.

Pesto, who lives at the Sea Life Melbourne Aquarium in Australia, is nearing the final stages of his first molt. It's a crucial period in a king penguin's life as it marks the beginning of independence as it prepares to leave the colony, the aquarium said.

King penguin chicks experience their first molt at around 10 months of age and the process can take up to six weeks depending on the aquarium. Because chicks expend a lot of energy molting, the animals often lose weight while growing their new, smooth feathers.

“As Pesto sheds his juvenile feathers and develops his smooth, waterproof adult plumage, he is looking more like an adult king penguin and is almost ready to move into the next phase of life as part of the colony,” a representative from the Marine Life Melbourne Aquarium shares with TODAY.com.

By growing these new feathers, Pesto is eventually able to swim. The brown feathers of king penguin chicks provide insulation but are not waterproof, which is why their adult plumage comes in handy.

According to the aquarium's website, he is expected to swim with other king penguins once the molt is complete. But for now, Pesto is rocking his “mid-toll” look for the world to see.

Pesto became an A-list animal star earlier this year thanks to his lavish lifestyle, eating up to 25 fish a day, and his adorable looks.

The Melbourne-based aquarium even held its own gender reveal of the penguin — and, of course, its fans — in September.

Many of the other penguins at Sea Life Melbourne Aquarium have become interested in pesto, according to the aquarium's website. His biological father, Blake, is the oldest and largest penguin in the facility.