(CNN) -- Fidel Castro's 85th birthday passed quietly Saturday -- in stark contrast to the week of celebration that preceded it.
Venezuelan President Hugo Chavez, a self-declared acolyte of Fidel Castro's socialist revolution, said Saturday on Twitter that he was celebrating Castro's birthday in Havana, where Chavez is currently undergoing cancer treatment.
"Here with Fidel, celebrating his 85th birthday," Chavez tweeted.
"Viva Fidel!" he added.
The week of events to mark Castro's birthday culminated Friday with a gala. The so-called "Serenade to Fidelity" was marked by a three-hour performance by artists from Europe and Latin America, including the Grammy-award winning female voice of the Buena Vista Social Club, Omuara Portundo.
Revolutionary fighters from the 1953 Moncada barracks attacks, considered to be the starting point of the Cuban revolution, participated in the event.
Ernesto "Che" Guevara's relatives were also present, reported Granma, Cuba's official Communist Party publication.
Castro was born on August 13, 1926, to a wealthy Spanish landowner and his household servant.
Considered "the father" of Latin American socialism, Castro is an icon to many leaders of Latin America's emerging left, who grew up in a generation of U.S.-backed dictatorships.
Castro ruled Cuba as until he officially stepped down in 2008 and handed powers to his brother, Raul Castro.
Castro, who appears to be frail and in poor health, has not been seen in public in recent days.