Spanish conservative politicians have criticised Madrid city hall for allowing a drag queen to take part in an Epiphany feast parade, arguing it is “distorting” an event aimed at children.

La Prohibida (The Forbidden) will star on one of the floats in the event on Friday in the Puente de Vallecas district in southern Madrid, one of 17 Epiphany feast parades planned for the Spanish capital.

The parades are held across the country each year on the eve of the Feast of the Epiphany, which celebrates the coming of three wise men with gifts for Jesus.

Children write letters to the Magi asking for gifts, which are left for them on 6 January, a national holiday. The celebration is more popular than Christmas in Spain and in parts of Latin America.

La Prohibida tweeted that she would wear teddy pyjamas at the parade.

Critics complained that Madrid city hall should respect the parades’ traditional form. “Epiphany should be respected, just as we would respect any festival of any religion,” said José Luis Martínez-Almeida, the spokesman for Spain’s ruling conservative Popular party at Madrid city hall, who opposes the city’s leftist mayor Manuela Carmena.

He accused Carmena, a former Communist party member, lawyer and anti-Franco activist before the dictator’s death in 1975, of “distorting Christmas”.

The float featuring La Prohibida was proposed by Orgullo Vallekano, a gay rights association based in the Vallecas district, whose local football club, Rayo Vallecano, in 2015 wore rainbow shoelaces during a La Liga match as part of a campaign against homophobia in football.

Francisco Perez Ramos, a city councillor with the leftwing coalition Ahora Madrid, which governs the Spanish capital, said the parade would “be respectful of children, of their dreams, and of the character of this festival.”

La Prohibida said the float aimed to defend “diversity and equality” and questioned on Twitter why nobody had complained when previous parades featured people dressed up as Star Wars characters that had nothing to do with Christmas.

Two years ago the Vallecas district chose a woman to represent one of the three kings at its Epiphany parade to promote equality.