On the day John Lennon was shot I had arranged to meet our lead guitarist in town to help me choose a new guitar. We had a band called "Highly Contagious" - wishful thinking, as it turned out. It "came" to us one evening in the pub after rehearsal.

Our lead guitarist had a cold, it was his idea, he thought it was great, he was the best guitarist and the boss and we were stuck with it. Infected. We got posters printed. It was a cheap, one-colour job on A4 paper. A rip-off at half the price. It was the two words of our name separated by a red cross sign in red. One of our supporters - one of my big sister's hippie friends - displayed one of our posters in his shoe-shop window. He took it down after a day because it was frightening old women away. He believed he lost a few pounds on our account, and I think if we were older and wiser he might have claimed damages.

I woke late that day, as befitted a developing rock star. I was going out with a girl in the Civil Service and she rang to tell me that John Lennon was dead. She delivered this stunning, dreadful news wrapped in a confection of Civil Service jokes and puns: "Did you hear John Lennon's dead - imagine that, he was just starting over!" And she laughed her head off and told me all about the clever guy who'd thought up all these clever jokes here, now, on the spur of the moment. She later married him. Which was just as well, because I knew there and then that she wouldn't be marrying me. Then I thought she must be joking. She wasn't, but she had more puns and began to deliver them. I hung up as shook as if my brother had died. I switched on the radio and John Lennon was singing and I knew it was true.

The rest of that day is a dark winter blur surrounding one vivid image. Walking down O'Connell Street with my new guitar, a dark winter's evening around six, cold and foggy, the newspaper stands with the news of Lennon's murder, and all the different papers with variations on the same headline. That image remains strongest, isolated, in slow motion, as textured as film.

I never took to that guitar. It was due to the lead guitarist's taste. As the day of the purchase drew close, he advised me to think deeply about myself to try to discover if I was a Gibson man or a Fender man. Gibson and Fender make guitars with different sounds. Our lead guitarist was a Gibson man, and while he admired some Fender men, he was quick to point out their limitations.

As it turned out, I could afford neither a Gibson nor a Fender, and settled for a minor name guitar which looked and sounded quite like a Gibson but not as good, of course. Later I discovered I was, deep down, a Fender man. But by then it was too late - my life had totally changed direction.

One month after John Lennon died, I left my girlfriend in the Civil Service, left the band, and traded the guitar in for an acoustic to go solo; a move which led, quickly and directly, to international anonymity.

It was many years later before I saw the connection between the two events. That day, that moment in O'Connell Street, surrounded by cartoony headlines in a surreal world of Lennon singing So This Is Christmas everywhere, his famous name in bold print shot dead, swirled around me like a phoney world of my own creation, lost in the depth of winter with a shiny new guitar.

My hero slain.

A fan. A mad fan, but still a fan. Not hungering to kill, but ravenous for the life he had. To somehow take it and keep it, a mistaken connection to reality at last.

Our life together, the Mark and the John of it, the fan and the star of it, the phoney fixated world of the dream-chaser in which I was neither and both. And now the undeniable truth that all lives are finite; and more often than not, end far sooner than we think they will.

It was the end of a romance, laid bare beneath the tacky electric splendour of Christmas lights. And once outside, there is no way back into the dream. I read the news that day as a boy.

Eamonn Kelly's plays include Religious Knowledge and Frugal Comforts. He has also written for radio and TV and is developing a TV sitcom with Big Yes Productions