Neil Diamond arrived at Fenway Park practically unannounced seven years ago, on April 20, 2013, as the Red Sox played their first home game since the Boston Marathon bombing.

Of course, many will remember it as the day Red Sox slugger David Ortiz spoke some unforgettable words, ultimately proving to be a city’s rallying cry.

But with emotions clearly at a high, Diamond delivered a powerful moment of his own as he led the crowd at Fenway with an eighth-inning rendition of “Sweet Caroline.” Seven years later, Diamond explained how the idea of him traveling to Boston, and the extraordinary day in general, came about.

“I saw the announcement that the bomber had been caught and the game would go on. The more I thought about it, the more I just knew I had to be there,” Diamond told Red Sox historian Gordon Edes. “It was the night before the game. We were at home in Los Angeles and I told my wife Katie that we needed to go.

“At 4 a.m., we boarded a plane to Boston with no real plan other than to make our way to Fenway. No one was aware we were coming, but it felt so right that neither my wife nor I questioned it. We landed in Boston a little more than an hour before the game started.”

Diamond admitted he really didn’t have a plan when he got to the ballpark. But it quickly became something those in attendance, and those that would hear see it, never would forget.

“There was no band or music prepared for my appearance. I didn’t really have a plan. They handed me a microphone, I walked out on the field between home plate and first base and was careful not to step on the line,” Diamond said. “I sang along to the recorded version of the song that they usually use, so there were actually two Neil Diamond’s singing, the 1969 Neil and the 2013 Neil. I was just singing along with everyone else.”

It’s become something he himself never will forget, either.

“It was a very powerful moment with the audience joining in as one. There was a feeling of relief, unity, strength and love. I saw people in tears, people hugging. It was a moment that I will never forget,” Diamond said.

“This day is among the most memorable of my career, and it was totally unplanned and unprepared. Maybe that’s where God came into the picture and helped it all come together in such a beautiful and spontaneous way.”

What an impromptu memory it was.