By Cate McCurry, PA
Irish premier Leo Varadkar is taking part in Belfast's Pride parade for the first time.
The Taoiseach joined thousands of people attending the march in the city centre.
His presence will be seen as significant as same-sex marriage remains a contentious political issue in Northern Ireland.
The parade, which kicked off from Custom House, is making its way through the city.
Mr Varadkar's visit comes two years after he attended a Pride breakfast to promote the rights of the LGBT community.
Ireland's first openly gay premier was not able to attend the parade that year as he had other official engagements.
In June last year, after meeting with senior leaders of the Orange Order and representatives of the two main communities in Belfast, he stopped for a pint in the city's popular gay bar, The Maverick, where he spoke to staff and a number of customers.
Mr Varadkar also joined 60,000 people in Dublin for its Pride march in June this year.
Addressing a huge crowd that gathered in Custom House Square, Mr Varadkar said that Northern Ireland's biggest parade isn't orange or green, but "rainbow-coloured".
He added: "I want to say how great it is to be in Belfast today.
"I always say the biggest parade that happens in Northern Ireland isn't orange or green, it's rainbow-coloured. It's really great to see it today.
"I had a real honour today to walk with Lord Hayward, who, along with Conor McGinn, put the legislation through the Commons and Lords to bring about marriage equality here in a few months' time. So we really want to thank them.
"What we see today in Belfast is Northern Ireland at its very best. Open, inclusive, diverse and for everyone.
"Thank you so much and happy Pride."
Pride celebrations are continuing in Belfast City Centre. It’s estimated around 60,000 people are attending today’s festivities: pic.twitter.com/2Y2xtG9xD5— Q Radio News (@qnewsdesk) August 3, 2019
Northern Ireland remains the only part of the UK where gay marriage is illegal.
That could change however, after landmark legislation was passed by the UK Parliament which will allow same-sex marriage in the region if devolution is not restored by October 21.
The changes will not come into effect if Northern Ireland's two main parties, Sinn Fein and the DUP, can reach an agreement to form a new Executive before the deadline.
Talks have been ongoing since May after journalist and gay rights campaigner Lyra McKee was shot dead while she was reporting on riots in Londonderry in April.
Belfast Lord Mayor John Finucane is leading the parade, which he said is one of the highlights of his year as mayor.
On Friday the Sinn Fein councillor received the first Pride flag that is flying from City Hall.
The rainbow flag was delivered down Belfast Lough on a flotilla of boats blasting their horns to cheers from onlookers on the banks on Friday evening.
Mr Finucane helped erect the flag at City Hall early on Saturday morning.
It will be the first time a Pride flag has flown from the landmark building.
Mr Finucane said: "This was an excellent event organised by Belfast Pride, they had a flotilla coming down the Lagan to present me with one of the original Gilbert Baker Pride flags to mark the significance of the Pride flag flying over the City Hall for the first time in our history as a city tomorrow and to celebrate what I think will be the biggest and the best ever Pride festival in Belfast," he said.
Meanwhile, the head of BBC Northern Ireland addressed the "confusion" around staff members attending Belfast Pride saying the broadcaster is not participating corporately.
The BBC has faced questions over impartiality - given that same-sex marriage is a contentious political issue in the region - since announcing staff in the organisation's BBC Pride group would be attending the event.
A memo to workers issued last week said staff would be participating in the annual Pride parade wearing BBC-branded T-shirts.
A statement also mentioned BBC Northern Ireland in the context of employees taking part.
BBC NI director Peter Johnston acknowledged there had been "confusion" about the "terms and basis for BBC staff involvement in the Belfast Pride parade 2019".
He said while members of the BBC Pride staff network - an employee-led initiative - would be taking part, BBC NI as a corporate body would not.
"We know that there are legislative issues specific to Northern Ireland in relation to same-sex marriage," he said.
"These raise important considerations for the BBC in the context of its editorial guidelines, including the requirement to maintain due impartiality within our output.
"None of this means that members of the BBC Pride network cannot be involved in Pride festivities in Belfast, but it does require BBC Northern Ireland to avoid creating the impression that it has a position on matters of political contention or controversy.
"The BBC's editorial guidelines provide clear advice in this regard. It is on this basis that BBC NI will not be involved corporately in the Belfast Pride parade and that individual programme brands will not be represented."
Ulster Television (UTV) staff members are also taking part in Belfast Pride for the third time on Saturday.
The ITV-owned organisation participated in the event for the first time in 2017, with several well-known UTV broadcasters taking part.
A spokeswoman for UTV said the company was proud to be involved.