Sister Teresa Forcades from the Benedictine monastery of Montserrat has a degree in Public Health from Harvard University in America - one of the world's finest educational institutions.
She has written critically about the Catholic church in the past as misogynistic and uncaring.
Sister Forcades plans to try and unite Catalonia's left-wing parties to bring about an independent state.
She had lived in the monastery for twenty years before moving into politics.
The elections are due to take place in September 2015, and Sister Forcades was selected as the number one candidate in the ballot list of Proces Constituent a Catalunya, a group she founded.
It calls for an independent state with a nationalised banking and energy sector, no armed forces, payment for stay-at-home parents and the opportunity to have abortion on-demand.
She has a large social media following and her YouTube videos speaking of the problems of global capitalism and 'big pharma' have been viewed by hundreds of thousands of people.
But she has admitted being a nun can have its drawbacks in politics.
Speaking to The Sunday Telegraph she said: "I know there will be people who will be deterred from voting for me because I'm a nun."
She added that speaking openly against the Church might have helped her popularity though.
Currently Sister Forcades is waiting for permission for her exclaustration, a period spent outside of the convent, before she moves to the political stage.
She has not spoken of leaving forever though: "I feel attached to the monastery.
"I feel I belong there. I am very happy the sisters agreed to let me do this for three years.
"We are ready in this country for major chance and I am ready to play a part in it."
