Berlin's Tierpark Zoo presented the pair, both female, to the media yesterday and even hardened news photographers cracked a smile when the cubs stumbled through the grass.
They're still a little smaller than a house cat and both have smooth black fur and green eyes that appeared to match the grass around them.
In the wild black panthers usually live for up to 12 years but born in captivity the baby panthers may live up to 20 years.
He was rescued by zookeepers, who fetched him out of the bear compound in a fishing net, and hand-reared with round-the-clock care by his devoted keeper until he became too big and too dangerous to have close contact with human beings.
Knut, who is a healthy 2-year-old animal now, became a celebrity bear and the darling of Berliners. His first birthday drew fans from around the world to Berlin.
TV stations from all over the world came to film the polar bear cub and international tourists were flocking to the zoo to see its major attraction.
He brought in some 500,000 extra visitors and the zoo sold merchandise ranging from cuddly toy bears to Knut-shaped candy bears, pulling in some $10 million in revenue.
However, Knut may not remain the only celebrity in German zoos. Only a few days ago a two-month-old female Bengal tiger cub made her first public debut in a zoo in the eastern German town of Aschersleben.
The cub, abandoned by the mother at birth, is being raised by the zoo director in his living room and it is being hand-reared.
After the twin panther cubs drew so much media attention, this white baby tiger, who does not have a name yet, stands a pretty good chance to turn into a tourist attraction, following in Knut's footsteps.