A photograph has emerged showing the view from the cockpit of a U-2 spy plane observing the Chinese balloon flying over the US.
The curvature of the earth is visible in the shot along with the balloon which was flying more than 18km above Earth.
The 60-metre tall balloon rigged with solar panels and mysterious equipment the US says was used for spying, which was shot down over the US east coast on February 4.
US Gen Glen VanHerck said it was carrying a payload of about 1,000kg of equipment.
The Chinese government claimed it was for meteorological purposes, but on Sunday, the US Secretary of State Antony Blinken said it had been sent to monitor the US military sites.
The image was first posted on the blog Dragon Lady Today, which is run by author Chris Pocock, an expert on U-2 spy planes. It is not clear how he obtained the image, which he also posted on Twitter.
Pentagon deputy press secretary Sabrina Singh confirmed the photo's authenticity on Wednesday and said the image would be publicly released shortly
In the image, the U-2 spy plane, nicknamed Dragon Lady after a CIA reconnaissance programme of the same name, can be seen soaring above the balloon with the curvature of the Earth visible on the horizon.
Zooming in, an aviation enthusiast on Twitter noticed that the shadow of the spy plane was even visible on the side of the balloon.
U-2 spy planes can reach altitudes of over 21km, and given the altitude of the balloon, it seems likely the aircraft was flying close to its maximum operational altitude.
Commercial aircraft fly between 10km and 12km at cruising altitude.
U-2 spy planes entered service in 1956 and conducted numerous reconnaissance missions over the Soviet Union. In this instance, the plane would soon be joined by a much more recent aircraft, the F-22 stealth fighter, which was used to shoot the balloon down.
The image represents a rare mission for the U-2 over US soil. The decades-old aircraft is expected to be replaced soon with a new aircraft code-named RQ-X, according to Skunk Works, the experimental design arm of Lockheed Martin, formally known as the Advanced Development Programs department.
Until then, the U-2 will become part of the US Advanced Battle Management System, a project to ensure rapid communication between different branches of the US military over vast distances, hosting sensors and encrypted communications equipment.
