Bei Bei’s birthday will be a bittersweet one.
The giant panda cub was born to mom Mei Xiang and dad Tian Tian at the Washington National Zoological Park on Aug. 22, 2015.
 Photos: See Bei Bei Grow From Cub to Giant Panda
To celebrate the big day, Bei Bei will get to munch on a frozen birthday cake created just for him by the Zoo’s Department of Nutrition Science, the zoo’s website says.
The fan favorite’s fourth birthday marks his final days in D.C. as the zoo prepares to return him to his native China.
Any cubs born to Mei Xiang and Tian Tian belong to China and must be sent back at age 4 to be part of the breeding program there, according to the zoo’s arrangement with the China Wildlife Conservation Association.
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Bei Bei’s older sister, Bao Bao, moved to China in 2017.
Bei Bei’s moving date is not yet official, the zoo’s website says, but guests will have plenty of time to visit him before he departs in the coming months.
As of Monday morning, the Giant Panda House is closed to give possibly-pregnant Mei Xiang some peace and quiet, but you can still see Bei Bei and Tian Tian outside.