If you're walking down the streets of Dublin today, you may come across an enormous painting that depicts two men locked in a moment of love. Artist Joe Caslin and photographer Sean Jackson worked alongside two models to create the pro-equality mural that's been painted on the side of a four-storey building ahead of the country's referendum on same-sex marriage next month. The team worked overnight to complete the painting, which is situated on South George Street in Dublin's city centre.

Ireland is a traditionally Catholic country, with homosexuality only decriminalised in 1993. Consequently, some dated attitudes remain in the country, and same-sex marriage is still outlawed. Caslin's intention to spread his art's message through Twitter and Instagram has worked, with many Dubliners posting photos of the work along with captions expressing support for equality. One of the models involved with the project posted a picture of the mural with the message, "If you think marriage equality doesn't concern you, it does."

Caslin spoke to Dazed about the project and what he thinks the outcome of the referendum may be. "It's a difficult one to call as we're the first country to hold a referendum and give the decision to the public," he says. "We have moved on a lot as a country in the last 25 years. We have moved on from the institutionalism of the Catholic church, it holds less resonance. When I was growing up in the 80s we were a very insular nation, but it's not like that any more."

The project is inspired by a Frederic William Burton painting called "Meeting on the Turret Stairs", another piece of art that depicts a love forbidden by a higher power. Burton's painting was in turn inspired by a 1,000-year-old Danish ballad that told the story of ill-fated lovers, unable to act on their desires.

Barry Jeffers and James McLoughlin are the two models that posed for the photograph. Both are gay Dubliners. "They're best mates," explained Caslin. "It needed to be people who are in that kind of scenario, immersed within that battle. The lads were brilliant, it was such a lovely project to work on because they knew that there was a power and an energy within the story that we were about to tell."

The referendum takes place on May 22 and proposes this amendment to the law. “Marriage may be contracted in accordance with law by two persons without distinction as to their sex.” If passed, this will afford same-sex couples the ability to tie the knot and enjoy the same civil rights as heterosexual couples.

Caslin has used street art as a medium for lending support to demonised groups before. In 2012, he painted a 40ft mural of a "teenage hoody" on a wall in Edinburgh, in the hope of "giving them a voice and a tangible presence within the city".

With just over a month to go before the referendum, Caslin's work is only likely to benefit the pro-equality push.