The park said An An was 35 years old this year, equivalent to 105 years old for humans, and was the world’s longest-living male giant panda under human care in history.

It called on the public to leave messages on its Facebook page to express the blessings to An An, "Let's cheer him up and get him back on!"

Then 20-year-old An An, together with 12-year-old female giant panda Jia Jia, was a gift from the central government to Hong Kong on the second anniversary of the city's handover.

They arrived in Hong Kong on March 11, 1999, and have been living in Hong Kong ever since, but Jia Jia died in 2016 due to a rapid deterioration in health.