So sweet: Polar bear gives birth to the cutest baby cub at Berlin Zoo

This is adorable.

A polar bear in Berlin Zoo has welcomed her third son, with photos released by the zoo show the pair snuggled up in their habitat.

Tonja, the polar bear, had been snoozing for 22 hours a day up until the birth.

She had also piled on more than 300 pounds during her pregnancy.

However, the news of her bundle of joy was slightly bittersweet, an unnamed 26-day-old infant in January, and her four-month-old Fritz, who died of hepatitis last year.

Dr Florian Sicks, who works at the zoo, watches the animals soon after the birth from a camera inside Tonja's enclosure. 

She said, "When around 9pm on December 1, loud smacking noises were heard for the first time for a long time, my first tension eased a bit.''

She continued, ''Meanwhile, the polar bear cub regularly drinks and approaches a rhythm of about 2-3 hours."

Tonja the polar bear, who previously lost two babies, has given birth to very cute son at Berlin Zoo.

For more about Tonja and her cub's story: https://t.co/Ytdg9wo5dc pic.twitter.com/adDtufdgs5

— Sky News (@SkyNews) December 3, 2018

Tonja, who had the cubs with a polar bear called Volodya, will be allowed to recuperate for a few weeks and no one will come into her cave.

And when can we expect the little bear cubs to come out?

In the spring – congratulations Tonja, enjoy your gorgeous little bear cubs.