Same-sex couples competed in the World Championship of Tango for the first time this year, with three male pairs and one female couple taking to the floor.
Cheers and applause reportedly rang out as the first couple, Juan Pablo Ramirez of Argentina, and partner Daniel Alejandro Arroyo Miranda of Venezuela, performed a 1940s classic.
“It takes two to tango,” Ramirez said after the performance. “But they don't necessarily have to be different sexes.”
The pair competed in the Salon Tango style qualifier round at the 10th edition of the Tango World Championship in Buenos Aires.
"There is a macho culture," Arroyo told AFP. "But there are older people who appreciate us.
"We aren't doing anything transgressive," he said, later adding: "society isn't ready. It's a slow change, with pauses."
A total of 556 couples from 37 countries have registered to compete in both categories, salon and stage over the two-week Tango festival at the Luna Park Arena.
Jesica Arfenoni and Maximiliano Cristiani from Argentina were named winners of the Salon Tango event. While fellow Argentinians Guido Palacios and Florencia Castilla won the Stage Tango.
The winning couples each received £7,000 and plane tickets to Paris.
Tango originated in 1890s Argentina and is believed to have been born in brothels where it was performed by pairs of men.
Women were initially prohibited from being involved in the dance.
Same-sex couples were never barred from competing in the World Championship of Tango but they had never previously entered, according to the competition’s director Gustavo Mozzi.