When Russian President Vladimir Putin walked alongside Chinese President Xi Jinping on Wednesday, a hot mic caught them talking about organ transplants and living to 150 years old. The moment came as Putin and Xi walked with North Korea’s Kim Jong Un at the head of a delegation of more than two dozen foreign leaders to watch a military parade in Beijing to mark the 80th anniversary of the end of World War Two.

The incident was broadcast live by China’s state broadcaster CCTV, which also shared the feed with global media outlets including AP and Reuters. According to China’s radio and TV administration, CCTV’s coverage was seen 1.9 billion times online and by more than 400 million on TV.

Biotechnology and Immortality

As Putin and Xi walked towards the Tiananmen rostrum where they would watch the parade with Kim, Putin’s translator could be heard saying in Chinese: “Biotechnology is developing continuously.”

The translator added, after an inaudible passage: “Human organs can be transplanted continuously. The longer you live, the younger you become, and (you can) even achieve immortality.”

Xi, off camera, responded in Chinese: “Some say in this century humans will live to 150 years old.”

Kim was smiling and looking at Putin and Xi but it’s not clear if the conversation was being translated for him. Putin can’t be heard clearly in Russian in the CCTV clip.

Putin Confirms Conversation

Putin confirmed later that he and Xi had discussed the topic on Wednesday. “I think when we went to the parade, the chairman talked about it,” Putin told reporters in Beijing when asked about the leaked conversation.

“Modern means of health improvement, medical means, even surgical ones related to organ replacement, they allow humanity to hope that active life will be different than it is today,” he said.

China’s Foreign Ministry and CCTV didn’t respond to Reuters requests for comment. As Xi started speaking, the video cut to a wide shot of Tiananmen Square and the audio faded. Just over 30 seconds later, Xi, Putin and Kim reappeared on camera as they walked up the steps to the viewing platform for the parade.

At the event, Xi addressed a crowd of more than 50,000 people, warning that the world faced a choice of “peace or war” as he inspected troops and military equipment, including hypersonic missiles and naval drones.Putin landed in China on Sunday for a Beijing-hosted summit with more than 20 non-Western leaders, including Indian PM Narendra Modi. He and Xi signed over 20 agreements on energy, AI and more and a new gas pipeline, but no details on funding and pricing.