While accepting his award for best original screenplay at last night's 81st annual Academy Awards, the 34-year-old first-time nominee and out gay man told the audience - and millions watching at home - how hearing the story of Harvey Milk as a 13-year-old boy gave him the hope to live his life openly, and maybe even fall in love and one day get married.
Dustin Lance Black said: "Oh my God. This was, um, this was not an easy film to make. First off, I have to thank Cleve Jones and Anne Kronenberg and all the real-life people who shared their stories with me. And, um, Gus Van Sant, Sean Penn, Emile Hirsch, Josh Brolin, James Franco and our entire cast, my producers Dan Jinks and Bruce Cohen, everyone at Groundswell and Focus for taking on the challenge of telling this life-saving story.
"When I was 13 years old, my beautiful mother and my father moved me from a conservative Mormon home in San Antonio, Texas to California, and I heard the story of Harvey Milk. And it gave me hope. It gave me the hope to live my life. It gave me the hope one day I could live my life openly as who I am and then maybe even I could even fall in love and one day get married.
"I wanna thank my mom, who has always loved me for who I am even when there was pressure not to. But most of all, if Harvey had not been taken from us 30 years ago, I think he'd want me to say to all of the gay and lesbian kids out there tonight who have been told that they are less than by their churches, by the government or by their families, that you are beautiful, wonderful creatures of value and that no matter what anyone tells you, God does love you and that very soon, I promise you, you will have equal rights federally, across this great nation of ours," he said to thunderous applause. "Thank you. Thank you. And thank you, God, for giving us Harvey Milk."
Speaking with reporters backstage, he said: "Harvey gave me his story and it saved my life, and I just thought it's time to pass it on. The only thing I knew I wanted to say was to tell those kids out there that they would be all right."
Sean Penn, who played the slain gay rights leader Harvey Milk in Milk, won his second Academy Award for best actor. His first was for Mystic River in 2004.
Harvey Milk is the first openly gay man elected to major public office in the US. Additionally, the film has also been in the spotlight following the passage of Proposition 8 - which rolled back the newly-won right of same-sex couples to marry in California - late last year.
"You commie homo-loving sons of guns," the actor began his speech as saying, drawing laughter from the audience. "I did not expect this, and I wanted to be very clear that I do know how hard I make it to appreciate me, often. But I am touched by the appreciation."
"For those who saw the signs of hatred as our cars drove in tonight, I think it's a good time for those who voted for the ban against gay marriage to sit and reflect on their great shame and their shame in their grandchildren's eyes if they continue that support," Penn said referring to anti-gay marriage protesters who had been picketing outside the theater. "We've got to have equal rights for everyone."
The big winner at this year's Academy Awards ceremony was Slumdog Millionaire which won eight Oscars, including best picture and best director for Danny Boyle (Trainspotting and 28 Days Later). Set largely in Mumbai, India, the 'Bollywood' melodrama tells the story of an orphaned Mumbai boy who grew up in the slums and becomes a contestant on the Indian version of Who Wants To Be A Millionaire?
Slumdog's main competition, The Curious Case of Benjamin Button which stars Brad Pitt and Cate Blanchett, won just three Oscars, all in minor categories. The film had led the pack with 13 nominations.
The late Heath Ledger won the award for best supporting actor for his role as the Joker in The Dark Knight which also picked up an award for sound effects.
The best supporting actress went to Penelope Cruz for her performance in Vicky Cristina Barcelona, making her the first Spanish actress to win an Oscar. In it, she plays Maria Elena, a woman who has a relationship with Cristina (Scarlett Johansson) and Juan Antonio (Javier Bardem).
And Kate Winslet finally won hers - on her sixth try, taking home the best actress prize for the Holocaust drama The Reader.
For complete list of winners, click on to oscars.org.