JOHANNESBURG (Reuters) - South African anti-apartheid and gay activist Simon Nkoli, who organised Africa's first Pride march in 1990, died 25 years ago but a group of artists inspired by him are determined to keep his legacy alive in an opera celebrating his life.

"Vogue Opera" - a mix of classical music, hip-hop, protest songs and dance - tells the story of Nkoli, whose activism helped to enshrine gay rights in South Africa's constitution - the first country on the continent to do so.

"He brought that for us, it was a gift," said composer Philip Miller, known for his work on fellow South African artist William Kentridge's "The Head and the Load", a performance piece about Africans' role in World War One which premiered at London's Tate Modern in 2018.

Miller, who said he met Nkoli in Johannesburg while exploring his own sexual identity, used elements of LGBTQ+ ballroom culture, which originated in the 1980s in New York's historic black neighbourhood of Harlem as a form of protest against oppression.

Dancers and singers walk on a runway in colourful and glittering costumes in front of a projected screen which displays archival pictures.

The opera, which premiered at Johannesburg's Market Theatre on Nov. 17, looks back at key moments in Nkoli's activism and personal life such as coming out as gay and HIV-positive, tracing his relationship with a white man during apartheid, when inter-racial dating was banned.

Nkoli faced prejudice even from fellow anti-apartheid activists while serving a four-year prison sentence on treason charges when he revealed his sexuality.

"We enjoy our freedom, but we never really know some of the people that paved the way, and so, when stories like this are being told, you finally get to just appreciate those that came before us," said Abiah Mahlase-Muttit, a fashion designer who attended the show.

The opera reveals not only Nkoli's struggles but also the happiness he brought to others.

"He was very political, and very clear about standing up for justice, but he also believed in having a good time, in fashion, and indulging himself into the joyful things that might seem frivolous to some people," Welcome Mandla Lishivha, the show's publicist and researcher said.

The opera's creators hope to take it around the continent or the world next year to highlight discrimination that the LGBTQ+ community continues to face.

Same-sex relations are legal in only 22 of Africa's 54 countries, and are punishable by death or imprisonment in some, according to a global review by the International Lesbian, Gay, Bisexual, Trans and Intersex Association (ILGA).

"If there isn't social buy-in, we're not done," the show's co-writer and rapper S'bo Gyre said.

(Reporting by Catherine Schenck, Thando Hlophe and Anait Miridzhanian; Editing by Emelia Sithole-Matarise)