When Pope Francis celebrates Mass during his visit to Cuba next month, he won't be alone. Looking over the pontiff's shoulder will be the revolutionary Ernesto "Che" Guevara -- or at least his portrait. Workers began setting up Monday the altar for Pope Francis in Havana's Plaza de la Revolución, which features a 118-foot image of Guevara's face on the side of a building, Agence France-Presse reported.

Guevara, an Argentine doctor nicknamed "Che," is a controversial figure. He met Fidel and Raul Castro in the 1950s, and together they worked to overthrow the Cuban dictator Fulgencio Batista Zaldívar. After the Cuban Revolution of 1959, he went on to become a military adviser, president of the Cuban national bank and minister of industry before leaving the country to spread revolution. He was executed by the Bolivian army in 1967. Guevara is known worldwide as a symbol of communist revolution, according to the History Channel.

Pope Francis, like Guevara, is from Argentina. He recently played a key role in brokering a deal to restore diplomatic relations between Cuba and the United States. The papal visit, scheduled for Sept. 19-22, is considered a landmark event.

Francis won't be the first pope to speak under Havana's huge Guevara portrait. John Paul II did so in 1998, saying that Guevara was now "before God's Tribunal" but was certain "he wanted to serve the poor." Benedict XVI followed suit in 2012, urging Cuba to embrace "genuine" religious freedom.

Francis has already run into Guevara's image at least once this year. When he spoke at the Meeting of Popular Movements in Bolivia on July 9, he was introduced by Bolivian President Evo Morales, a leftist who was wearing a jacket with Guevara's face on it.

After the pope leaves Cuba on Sept. 22, he will go to the U.S. He is expected to meet with President Barack Obama, address Congress and celebrate Mass at the World Meeting of Families in Philadelphia. See the full itinerary here.