A press release from the United Nations Human Rights names Celina along with pop star Ricky Martin, and Brazilian singer Daniela Mercury who have taken the pledge to support the campaign.
The Free & Equal campaign aims to raise awareness about homophobic and transphobic violence and discrimination, and encourage greater respect for the rights of LGBT people.
When contacted in Singapore, Celina said: "I have spent half of my life fighting for the cause and finally with the backing of United Nations Human Rights and with the help of people I respect and love, I can take the campaign to another level. To get a platform like this to reach out to people across the world is a dream come true."
The No Entry fame actress feels there is a long way to go before we come anywhere close to realising equality for the LGBT community in India.
"In India, there is only lip service for them. Equality is a basic human right and it cannot be denied to any community. There is a lot violence against the LGBT community across the world. At least in Mumbai they are relatively safer."
For Celina even getting important people to support her cause is impossible.
"A lot of people in the entertainment industry feel that if you support gay rights, you might be considered a part of the gay community. Through the United Nations' campaign I hope to broaden the base of understanding the problems of the LGBT.
"At the moment in India, we only have tolerance, no understanding for the community, and that too in selected enlightened sections of society. I feel mainstream sections are only able to mask their intolerance towards homosexuality. Is that enough?"
Celina recalls with shock and disgust the incident involving the Aligarh Muslim University professor Shrinivas Ramchandra Siras, who was caught on camera making love to a man. He later died under mysterious circumstances.
Wonders Celina: "What was that poor man's fault? That he preferred people of his own sex? It's okay if people prefer not to come out of the closet. But if they do they should not be punished for it.
"Gay people should not be segregated at work places or in social spaces because of their sexual preference. I hope to work towards that through the United Nations initiative."
Right now Celina's prime focus are her twins.
"Until they are two, they need me and I need them too. So I am completely focused on that, though I still need to keep going to Mumbai constantly for my endorsement activities. Once the twins start going to play-school after three months, I'd have a bit more time on hand."
Celina also intends to start producing films from next year.
"But my first production would not have me in the cast," she said.