He opened up about the traumatic event

The 51-year-old appeared on the Late Late Show with Seth Meyers where he explained the tale.

Initially, he said he was struggling to urinate.

"I'm like, ‘Oh, this doesn't feel right.’," he said.

“I knew I had to, and then silly Stephen thought, 'Oh, well, if I go back to my seat and I just keep drinking water, at some point it will happen.'"

The Brit explained after around an hour he went to the toilet again, but "long story short, all of a sudden I went, but it was just pure blood."

He continued: “I couldn't stop this trajectory of blood and I'm having a slight panic attack. I'm about to cry and I'm having a moment.”

In his moment of panic, Graham remembered that he took a selfie with a fellow passenger before getting onboard the plane, and that they happened to be a doctor, and so he sensibly called for their help.

"Next minute, the doctor comes around the corner, and he goes, ‘Stephen!’ and I'm like 'Doc, hello!', and I explained the situation,” he said.

"He had another friend with him, who was a surgeon, so I'm there, and I explain. He's like, okay and the surgeon, Dr Haji, says, we can work this out."

The Thousand Blows star explained that the pair sterilised the lounge area between economy and first class, and sourced a catheter from a medical box for emergencies.

"I drop me kecks, I get on the couch, and he performs a catheter operation there and then,” he explained.

"The relief was unbelievable as you can imagine. It was a little clot that had got stuck behind, well, not little, but, had got stuck behind my urethra.

"I went to the toilet, and it was one of the nicest experience with me and my penis!"