Belfast City Hall will be lit up in rainbow colours to mark the anniversary.
Today marks 40 years since a landmark judgement, that decriminalised homosexuality in Northern Ireland.
Local activist Jeff Dudgeon took on the law that saw gay men thrown in jail - and won.
The decision also paved the way for ensuring no other EU state could ban homosexual acts.
The building in Belfast city centre is already being lit up in rainbow colours tomorrow to mark 40 years since a landmark court case ruling that led to the de-criminalisation of homosexuality in Northern Irelandhttps://t.co/gBQ1oXn4LN
— The Irish News (@irish_news) October 21, 2021