This shy looking joey is the first Goodfellow's tree kangaroo to be born in the UK and Ireland - and it's at Belfast Zoo.
It's too early yet for the thrilled keepers to determine the gender of the new arrival, which is expected to stay in mum Jaya's pouch for several more months before it starts to explore.
The zoo is home to the only Goodfellow's tree kangaroos in the UK and Ireland - in fact there are only 22 tree kangaroos in the whole of Europe, and only six of this subspecies.
Dad Hasu-Hasu and Jaya arrived at the zoo in 2013.
Zoo curator Andrew Hope said: "Like all marsupials, female tree kangaroos carry and nurse their young in their pouch.
"Keepers first noticed movement in the pouch back in May but it is only recently that the joey has started to make an appearance.
"The joey will remain in Jaya's pouch for several more months before starting to explore and, for this reason, it is not yet possible for keepers to determine the sex or the name of the latest arrival."
Belfast Zoo manager Mark Challis said: "Belfast Zoo is home to a number of extremely rare and endangered species and, while the team are always ecstatic when any of the animals successfully breed, we are particularly over the Moon with the arrival of the tree kangaroo joey.
"Only 13 zoos internationally are home to Goodfellow's tree kangaroos, so the arrival of our joey is spectacular.
"The population of Goodfellow's tree kangaroos has dramatically declined in the last 30 years due to the habitat destructions and hunting.
"Zoos have an important and active role to play in their conservation and I am proud that Belfast is leading the way for Goodfellow's tree kangaroo in the UK and Ireland."
Goodfellow's tree kangaroos looks quite different from terrestrial kangaroos.
Those that live on the ground have enormous back legs and are excellent at hopping, but a tree kangaroo's back legs are almost the same length as the front legs and hopping is awkward for them, but they can leap 30 feet from branch to branch.
Goodfellow's tree kangaroo has short, woolly fur, usually chestnut to red-brown in colour, a grey-brown face, yellow-coloured cheeks and feet; a pale belly, a long, golden brown tail, and two golden stripes on its backside. It can weigh up to 7.5 kilograms.
They prefer to live in mountainous rainforests in Papua New Guinea and Indonesia, eating leaves but also fruit, flowers and grass.