He has kept a low profile since sexual assault allegations emerged in 2017.
The actor resurfaced to recite the poem The Boxer by Gabriele Tinti in Rome.
It includes the lines: "The more you're wounded the greater you are. And the more empty you are. They used me for their entertainment, fed on shoddy stuff. Life was over in a moment."
The appearance at the Palazzo Massimo alle Terme came less than three weeks after prosecutors in the US dropped a criminal case relating to charges of indecent assault and battery.
London's Metropolitan Police are still investigating six allegations of sexual assault in the UK between 1996 and 2013.
The double Oscar-winner delivered the nine-minute poem next to a Greek sculpture titled The Boxer at Rest at the Palazzo Massimo, which is part of Italy's National Roman Museum.
It's written from the perspective of the boxer, who was immortalised in bronze. It reads:
"I shook the country, made the arenas vibrate, tore my opponents to shreds. I lit up the darkness, collected insults, compelled applause. Not everyone knew how to do this. None of you.
"On the other hand, life is not frightening for those who have never taken a risk. Who can understand me? Who can I speak to?
"The spirit is ill. It can no longer be cured. It will disappear off the face of the earth. This is its fate. I know now I am tired and becoming sad. And this is why you have dug me the grave."
Tinti said it was "an honour to have Kevin Spacey reading my poems", adding: "Rome loves you!"
Last December, Spacey posted a video to YouTube, appearing as his House of Cards character Frank Underwood, saying: "I'm certainly not going to pay the price for the things I didn't do."
BBC
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