Brian Cox was banned from attempting to make contact with aliens as BBC bosses were worried health and safety laws would be broken.
The science hunk's show 'Stargazing Live' featured a planet called Threapleton Holmes B, which had recently been discovered by two amateur astronomers, and Brian wanted to listen to the new planet live on air.
However, bosses wouldn't allow him to in case the corporation's strict editorial guidelines were breached.
He told BBC 6 Music radio: "We decided that we'd point the Jodrell Bank telescope at the planet that had been discovered by these two viewers and listen because no one had ever pointed a radio telescope at it and you never know.
"The BBC actually said, 'But you can't do that because we need to go through the regulations and health and safety and everything in case we discover a signal from an alien civilisation'."
The physicist admits he was shocked at the decision because he could have made such an important discovery.
He said: "You mean we would discover the first hint that there is other intelligent life in the universe beyond Earth, live on air, and you're worried about the health and safety of it?
"It was incredible. They did have guidelines. Compliance."
Host host Shaun Keaveny added: "The idea that intelligent life could be discovered and it might swear and that's why we wouldn't broadcast it - it's such a brilliant BBC thing, isn't it?"