That's one cheeky step for the United Kingdom.
British engineer Keith Wright, who worked on the first moon landing in 1969, is claiming that he secretly got astronauts Neil Armstrong and Buzz Aldrin to carry the Union Jack to the lunar surface.
He said he wanted to give Brits a bit of credit, according to the Telegraph.
"We were working on the experiments that the astronauts were going to put on the lunar surface. We had Neil Armstrong and Buzz Aldrin come to our facility for a run-through, "he told" The One Show "on BBC One.
"There were two brackets on the test which held the solar panels while traveling to the moon. We've got a ball pen and signed our names … I signed my name and I thought, well, I'll put 'UK.' Then I thought, I'll draw a little Union Flag.
"So we had a little Union Flag," he said, adding that the US flag was planted first, before the astronauts set up the solar panels.
The Nottingham-born engineer worked for de Havilland before moving with his family to the US, where he landed a coveted job on the Apollo space missions.
"Neil was very relaxed and quite jokey," he said about the legendary astronaut, the first person to set foot on Earth's close neighbor.
"We were concentrating so hard on doing our job, and seeing that they could do the job properly, it almost seemed normal. But, thinking about it afterwards, I did get their signatures, "he said.
Ryan Gosling's movie "First Man" did not show it being planted.
The omission sparked complaints, with Republican Sen. Marco Rubio calling it "total lunacy" – while Aldrin, 89, tweeted a picture of himself on the moon along with the words "proud to be an American."