Giant panda Tian Tian enjoys an ice cake at Smithsonian's National Zoo in Washington, DC, the United States, on Aug 27, 2023. (PHOTO / XINHUA)

Crowds joined a special birthday party this weekend at the Panda House at the Smithsonian's National Zoo and Conservation Biology Institute.

They flocked there to celebrate the 26th birthday of Tian Tian, a male giant panda living at the zoo in Washington DC.

At 9 am Sunday, keepers served Tian Tian a special panda-friendly fruit birthday cake in his outdoor enclosure. The keepers carefully decorated the three-tier cake: The number "26" was made from frozen diluted apple, with pineapple juice at the top.

Giant panda Tian Tian enjoys an ice cake at Smithsonian's National Zoo in Washington, DC, the United States, on Aug 27, 2023. Giant panda Tian Tian celebrated his 26th birthday at the zoo on Sunday. (PHOTO / XINHUA)

Tian Tian left the cake aside, focusing instead on licking a box smeared with honey. He then turned around to the three-layer cake, clutched it, and devoured it. The cake, coated with mashed sweet potatoes and honey, also contained apples, carrots, and bamboo sticks, which are the panda's favorite delicacies.

It was Tian Tian's final birthday at the zoo. He and Mei Xiang, 25-year-old, and their cub Xiao Qi Ji, 3, will leave in December and return to China, their home country

Some visitors sang Happy Birthday in unison. Many more panda lovers joined the festivities through the zoo's 24-hour live Panda Camera.

It was Tian Tian's final birthday at the zoo. He and Mei Xiang, 25-year-old, and their cub Xiao Qi Ji, 3, will leave in December and return to China, their home country.

According to the zoo's website, there will be a grand farewell event for the family of Mei Xiang, Tian Tian, and Xiao Qi Ji from Sept 23 to Oct 1.

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Pam, 52, a nurse living in Tysons Corner, Virginia, told China Daily that she got up early and drove to celebrate Tian Tian's birthday. "I must come because they will go back to China soon," she said, "I always came to see the pandas with my son when he was little. I hope they could come back someday."

Giant panda Mei Xiang enjoys an ice cake at the Smithsonian's National Zoo in Washington, DC, the United States, on July 22, 2023. (PHOTO / XINHUA)

An influencer, "DC Panda Girl", told China Daily that she goes to the zoo nearly every weekend to visit the pandas. She took lots of videos and photos and updated them on her YouTube channel.

"It will bomb me up. I do not know where to go after they are gone," she said.

"I feel sad, and my sister will be the saddest," said Charlotte, 7, talking about the pandas leaving and pointing to her sister, Lucy, almost 3, who was smiling and holding a panda doll tightly.

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The girls and their baby brother, 1-year-old Alex, and their mom, Malte, were all wearing pointy birthday hats with a panda sticker on each of them. They also lifted a golden bling handmade poster that read "Happy Birthday, Tian Tian".

Mei Xiang celebrated her 25th birthday on July 22, and the zoo celebrated Xiao Qi Ji's third birthday on August 21.

This photo taken on April 19, 2023 shows giant panda Xiao Qi Ji at Smithsonian's National Zoo in Washington, DC, the United States. (PHOTO / XINHUA)

Xiao Qi Ji was so lively Sunday, climbing trees, playing with toys, and being cute, distracting some attention and laughter from his dad, Tian Tian, the star of the day.

Mei Xiang, a female panda, and Tian Tian arrived at the zoo in December 2000 based on a 10-year cooperative agreement on giant panda breeding and research signed with the China Wildlife Conservation Society

Mei Xiang, a female panda, and Tian Tian arrived at the zoo in December 2000 based on a 10-year cooperative agreement on giant panda breeding and research signed with the China Wildlife Conservation Society.

In 2010, 2015, and 2020, the agreement saw extensions of five, five, and three years, respectively. The agreement expires at the end of 2023, marking the official repatriation of Mei Xiang, Tian Tian and Xiao Qi Ji to China.

Over her span of more than two decades in the US, Mei Xiang has successfully given birth to four robust giant panda cubs — Tai Shan, Bao Bao, Bei Bei and Xiao Qi Ji — all conceived through artificial insemination using Tian Tian's semen.

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While Tai Shan, Bao Bao and Bei Bei have already returned to China to participate in the giant panda breeding initiative, Xiao Qi Ji entered the world amid the COVID-19 pandemic, arriving at a remarkable time when his mother, Mei Xiang, was a venerable 22 years old — a notable age for a giant panda.

Visitors watch male giant panda Tian Tian enjoying his birthday cake at Smithsonian's National Zoo in Washington DC Aug 17, 2023. (PHOTO / XINHUA)

The journey of Xiao Qi Ji from birth to growth has captivated the interest of panda enthusiasts within and beyond the US. Notably, the moniker "Xiao Qi Ji" was the outcome of an online naming poll sponsored by the zoo, which received 135,000 votes.

Before Mei Xiang and Tian Tian, the zoo welcomed the first Chinese pandas, Ling Ling and Xing Xing, to the United States in April 1972. Last year, the zoo celebrated the 50th anniversary of the pandas' arrival with a series of events called the Pandaversary Party.