Gregorio arrived in Cuba when he was six years old, but, if we believe the implications of a mythical novel, he never stopped dreaming about the white beaches of his childhood or the "montañas pardas" (brown mountains). Year later, in 1928, a hurricane would unite his destiny to that of one of the best contemporary novelists as it was during this tropical storm that Gregorio and Ernest Hemingway first met. The writer returned to Cuba in 1934 and hired Fuentes to look after the 'Pilar', a small fishing yacht that had been named in honour of the patron saint of Spain. This was the start of a friendship that would last many years and involve endless long days of fishing.

They say that Cuba was the 'true' homeland of Hemingway, or at least the place where the writer felt most at home. His innumerable visits to the island always included many long fishing expeditions with Gregorio and, through this friendship, the character emerged that would eventually see the North American win the Nobel prize for Literature. Gregorio provided the inspiration for Santiago of 'The Old Man and the Sea', a timeless character: "The old man was thin and gaunt with deep wrinkles in the back of his neck. The blotches ran well down the sides of his face and his hands had the deep-creased scars from handling heavy fish on the cords. But none of these scars were fresh. They were as old as erosions in a fishless desert. Everything about him was old except his eyes and they were the same color as the sea and were cheerful and undefeated," wrote Hemingway.  

The writer also paid tribute to the islander from Lanzarote after receiving his prize: "To old Gregorio who I see every time I go to Cuba. He was born in the Canary Islands and for this reason they called him the islander. To escape from the misery, he arrived illegally in Cuba on an old ship, departing the Canarian coast as an illegal emigrant. I know his Cuban family, his children and grandchildren. His honest stories, told with simplicity, patience and humility, touched me and filled me with emotion. To my friend Gregorio, as it is he who deserves the Nobel Prize", Hemingway was reported as saying during a stay in Havana.

Gregorio and Hemingway became friends and the Canarian fisherman thought of the writer in this way until the day of his death. "We were very happy on that boat. They were years filled with adventure and we were young and full of life. All the memories that I have of Ernest are good", said Fuentes in a interview shortly before his death. The friends once embarked on a dangerous adventure during the Second World War. They mounted a machine gun on the edge of the Pilar and set out to hunt German submarines. It goes without saying that they failed to sink a single one.

The suicide of Hemingway (2nd July 1961) surprised Gregorio who maintained until the end of his days that the writer was the victim of a conspiracy due to his leftist ideology. From then onwards, Fuentes did not return to fishing and, even though the writer left the Pilar to him in his will, he did not wish to go to sea without his friend. Gregorio, Ernest Hemingway's Cuban friend, died in the small village of Cojimar (in the east of Havana) in January 2002.