Happy birthday to a giant panda.

Bei Bei turns 4 years old Thursday, and zoo officials said he’ll get a “panda-friendly frozen cake” to celebrate. It will be Bei Bei’s final birthday celebration in the nation’s capital before leaving the country.

As part of the National Zoo’s breeding agreement, giant pandas have to move to China when they turn 4.

Zoo officials said they don’t have an exact date for Bei Bei’s move, but they warned that plans are underway and that “it will occur in the coming months.”

Bei Bei won’t be the first giant panda to leave Washington for China. Bao Bao moved in 2017, and her older brother, Tai Shan, moved in 2010. Like most giant pandas around the world, they also were on loan from China. The National Zoo has had giant pandas since the 1970s.

Bei Bei was born Aug. 22, 2015, and is one of three surviving cubs of mother Mei Xiang. His father is Tian Tian. He is one of three pandas at the zoo now.

Earlier this month, zoo officials said Mei Xiang, who is 21, was showing changes in her behavior that could indicate she might be pregnant. She was artificially inseminated in March with semen from Tian Tian.

The zoo has closed off the Panda House to give her a quiet space. Female pandas are in estrus for only 24 to 72 hours each year and also can have false pregnancies.

Zoo officials said actions such as licking her paws, cradling toys and building a small nest of shredded bamboo in her den indicate she could be pregnant. Zookeepers have been performing regular ultrasounds on Mei Xiang, who is on the older side for giving birth, and are watching her closely.

But officials won’t know for sure if she’s pregnant until later this month.