CHENGDU - A pair of giant pandas will leave for Copenhagen, Denmark for collaborative research, a panda research base in southwest Chinese city of Chengdu said Wednesday.

Male Xing Er, a 5-year-old, and female Mao Er, a 4-year-old, will leave Chengdu at 7:30 am Thursday morning and head to their new home in Copenhagen Zoo, the research base said.

A farewell party for the pandas was held at the base Wednesday.

They will live there for 15 years, according to the agreement signed between the Chinese Association of Zoological Gardens and the zoo in 2017.

China and Denmark first agreed on the program during Queen Margrethe II's state visit to China in 2014.

Since November 2015, Copenhagen Zoo has sent veterinarians, keepers and nutritionists to the panda base in Chengdu. To better take care of them, project zoo workers will also learn Chinese.

The base has launched giant panda research programs in cooperation with 16 countries and regions so far, according to Zhang Zhihe, head of the research base.