OSCAR-WINNING actor Morgan Freeman has weighed in on Australia's marriage equality debate, saying once people start understanding that being gay isn't a choice then equal rights will follow.
The 80-year-old spoke to News Corp Australia after travelling to nine different countries with National Geographic on a mission to discover what things unite humanity.
Through filming his six-part series The Story of Us, Freeman says he has learnt that recognising what we have in common is the key to bringing people of different opinions together on divisive topics like marriage equality.
"I think one of the catalysts people have experienced here in America is the realisation that some of their relatives are gay," Freeman said. "What are you going to say if your 14 or 15-year-old son comes and says, 'Dad, I'm gay'. Some are excommunicated immediately but most aren't. There is a new mindset and an understanding that it isn't some choice you are making."
Freeman says one of his best memories of Australia was ending up in a gay bar in Sydney listening to We Are Family.
"It was so much fun and I thought there was this feeling of freedom," he said. "I am surprised Australia doesn't have marriage equality."
Freeman, along with his fellow executive producers Lori McCreary and James Younger, said the freedom to be able to express yourself and be who you are is a central theme of The Story of Us, a sequel to the Emmy-nominated The Story of God, also narrated by Freeman, which scored National Geographic the highest ratings the network has had for one of its series.
"It is the relationship with others that causes the change of heart," McCreary said. "I listen to news programs I don't agree with because I want to know what people are saying; I want to be able to have a dialogue.
"We hope this sort of show will open up cracks of little things of something that's common," she said.
The hour-long episodes of The Story of US tackle the concepts of Freedom, Love, War and Peace, Rebellion, Power and our idea of 'us and them'.
Freeman interviews dozens of diverse people with compelling stories.
There's Daryl Davis, an African-American blues musician who befriends KKK members and has single-handedly prompted hundreds of them to hand in their robes.
Then there is Victoria Khan, who was a child when she and her sister saw their whole Afghani village slaughtered. Khan ended up in a camp which trained children as suicide bombers before being rescued and eventually making her way to the US where she is living freely.
Freeman said he isn't preaching for world peace in the series, but for viewers of the show to walk away feeling hopeful that we are more alike than we are unalike.
"Life is like the ocean. It is never quite the same; it is never still. The concept of world peace is never going to be a reality because we are like water - we need balance," he said. "You can't have too much good because there is no way to measure it without the bad."
The Story of US premieres on Wednesday, October 11 at 8.30pm (AEST) on National Geographic. National Geographic is available on Foxtel, Foxtel Now, Fetch & the National Geographic App.