It was impossible to hear his music because the distance between me and him was some 50 metres and the 'Boom! Boom!' was too loud.
The picture was taken by Aris Messinis, a photographer for the AFP agency from Athens, and the caption information said the men were fighters of the National Transitional Council (NTC). Former "rebels" who were now the de facto government forces.
In many ways the photograph captured perfectly the ad hoc revolutionary spirit that has been displayed throughout much of the conflict by the former "rebels". Men, with no formal military training, but with an enthusiasm to see Gaddafi defeated threw what little they had at the dictator's standing forces - with the military might ofNato flying overhead.
But what set of circumstances would lead a musician to wield his guitar, rather than a weapon in the midst of a firefight?
Channel 4 News contacted the photographer, Aris Messinis, to find out the story behind the lens.
"That day the NTC fighters were trying to advance to the centre of the city and it was a heavy street fight with lot of incoming and outgoing firing. (AK-47, machine guns, anti-aircraft machine guns, RPGs, sniper firing)," Messinis told Channel 4 News.
Messinis was amazed to see the man playing guitar amidst the battle but the fighting was so hard it was impossible to cross the street to talk to him.
"I realised by looking at him through my camera that he was trying to encourage the other fighters.
"It was impossible to hear his music becaue the distance between me and him was some 50 metres and the 'Boom! Boom!' was too loud."
Such was the ferocity of the fighting one of Aris' fellow journalists was wounded by a mortar shell, highlight how dangerous the battle zone was.
Early on in the conflict Al Arabiya filmed Masoud Biswir, a rebel fighter with a guitar, singing to his comrades on the road, while carry an RPG strapped to his back.
"But," writes Aris, "The whole time that I was in that place I didn't saw him participating in the battle except his encouraging music."
As the war moved towards Libya's capital city Tripoli so the spotting of this warrior poet increased.
In Tripoli, Steven Sotloff of Time Magazine was in Martyrs Square as thousands of people flocked to it to celebrate the downfall of Gaddafi. Amongst the crowd was Masoud Biswir, with his guitar.
Sotloff writes in his September article: "The 38-year-old moved through the crowd with his guitar in one hand and his Kalashnikov in the other. Soon he was on a plywood stage as young girls in colourful headscarves were jumping and cheering. "My nation will remain strong, my nation will remain lofty, my nation will remain free," Biswir sang as the crowd roared.
Sotloff interviewed Biswir after the impromptu gig and learned that he was formerly a businessman from Benghazi who took up arms against Gaddafi.
"I was never a soldier," he told Sotloff. "But when others started dying, I felt it my duty to protect my people."
Sotloff is not the only journalist to have crossed paths with Biswir. Jason Koutsoukis of The Ageran into him on the road to Ajdabiya. People were running from explosions as Gaddafi's forces fought the rebels, all that is except for Biswir.
Koutsoukis reports that Biswir shouted to those fleeing, "Don't be worried, it's OK.''
My mother don't be worried, we know how to fight. We know how to make freedom. We know for what we die.Masoud Biswir
His report describes how "The blast interrupted an impromptu live performance of Mr Biswir's latest musical composition, a song about freeing his country from the rule of Libyan leader Muammar Gaddafi."
Such is Biswir's success, his song My Nation Will Remain the Same has become something of an anthem and has been covered by a rock and metal band in Tripoli and published on YouTube.
So, is the guitarist photographed in Sirte Biswir? The guitar is different but it certainly seems probable - after all how many wandering minstrels with AK-47s can there be in Libya?
Whoever it is, the spirit of Biswir's lyrics is certainly shared by those in the photograph: "My mother don't be worried, we know how to fight.
"We know how to make freedom. We know for what we die."