Same-sex marriage is now legally recognised in Northern Ireland.
Same-sex couples will be able to register to marry, meaning the first ceremonies will take place in February.
For couples who are already married, their marriage will now be legally recognised in Northern Ireland.
However, those who are already in a civil partnership will not be able to convert it to a marriage at this stage.
The Northern Ireland Office is set to begin a consultation later this year about converting civil partnerships and the role of churches in same-sex marriages.
Heterosexual couples will also be able to enter into civil partnerships.
When the Stormont assembly collapsed, marriage equality campaigners turned their focus to Westminster.
In July 2019, MPs backed amendments which required the government to change abortion laws and extend same-sex marriage to Northern Ireland if devolution was not restored by 21 October 2019.
Same-sex marriages have been allowed in England, Scotland and Wales since 2014, but Stormont did not legalise them.
Because couples have to indicate their intention to marry 28 days before doing so, the first weddings are expected to be held on the week of Valentine’s Day.
John O’Doherty from the Love Equality campaign said this was the “culmination of five years of campaigning for marriage equality and marks an enormous step forward for LGBT+ people”.
“There remain a number of issues to be addressed before couples in Northern Ireland have the same rights as those in other jurisdictions,” he added.
“However, we celebrate this remarkable achievement with the thousands of people who made their voices heard and demanded change in spite of the many barriers placed in their way.”