An open microphone recently captured a side conversation between Russian President Vladimir Putin and Chinese President Xi Jinping on Wednesday in Beijing about organ transplantation and the possibility of humans living up to 150 years.

This moment coincided with Putin and Xi walking alongside North Korean leader Kim Jong Un at the head of more than 20 foreign leaders watching a military parade in the Chinese capital marking the 80th anniversary of the end of World War II.

China Central Television (CCTV) broadcast this moment live and provided it to other media outlets, including the state-run China Global Television Network (CGTN) and the Associated Press and Reuters agencies.

The Chinese Radio and Television Administration reported that CCTV’s coverage of the event received 1.9 billion online views and more than 400 million TV viewers.

As Putin and Xi walked toward the Tiananmen platform where they watched the military parade with Kim, Putin’s interpreter was heard saying in Chinese, “Biotechnology is continuously developing.”

The interpreter added, “Human organs can be continuously transplanted. The longer you live, the younger you become, and you can even achieve immortality.”

In response, Xi, who was off-camera, was heard replying in Chinese, “Some expect that humans may live up to 150 years in this century.”

When Xi began his speech, the camera switched to a wide shot of Tiananmen Square, and the sound faded out.

After just over 30 seconds, Xi, Putin, and Kim reappeared on camera walking up the stairs toward the platform to watch the parade.