The story of Anthony Albanese being raised by his single mother, Maryanne, in public housing in Sydney's inner west is one he has told often in his political career.

"What I was told was that (my mother) travelled overseas, met my father, married him overseas, returned to Australia and that he died in a car accident," Mr Albanese told 7.30.

"That was what I was told, and from an early age, that was what I believed."

But when he was about 14 or 15 years old, his mother revealed that there was actually much more to the story.

"We sat down just after dinner one night and she — it was very traumatic for her, I think, to tell me that in fact that wasn't the case, that my father might still be alive, that she'd met him overseas, fallen pregnant with me, had told him and he had said, basically, that he was betrothed to someone from the town in Italy where he was from.

"I think that whole guilt associated with having a child out of wedlock in 1963 as a young Catholic woman was a big deal and, hence, the extent to which she had gone to in terms of adopting my father's name, she wore an engagement and a wedding ring, she — the whole family just believed this story."

Feeling a sense of obligation to his mother, Mr Albanese didn't follow up on details of his father until after his mother died in 2002.

"There was a particular time where we were visiting my mother's grave when [Albanese's son] Nathan was a little boy and he said, 'where's your Daddy?'"

"And at that moment, it hit me that ... I had a responsibility to him as well — he carried the name Albanese — and to find out more about my father.

"So it was very much a gradual need that became ... more and more a sense of urgency as it was clear to me as well that he would've been getting older and that I needed, I needed to know more about what had happened."

But how to go about finding a man separated by almost 50 years and half a world?

Searching for a needle in a haystack

Maryanne (right) with her brother and friends in the Fairsky dining room with Carlo Albanese (standing left) ( Supplied )

Mr Albanese had one crucial piece of information.

"We had a photo from the ship (the Fairsky) where he worked as a steward, which is where he met my mother on the journey across from Sydney across to London," Mr Albanese said.

"I realised that the ship cruise line was essentially taken over by Sitmar, which had been taken over by P&O, which had been taken over by Carnival and I knew Ann Sherry, the head of Carnival Cruises, and asked her if there was any assistance that she could give."

Ms Sherry couldn't promise anything but said she would ask around.

"She talked to a maritime historian, this wonderful man, Rob Henderson, who is just fascinated by maritime history," Mr Albanese said.

Mr Henderson just happened to be going to a conference in Bari, in southern Italy, and said he would make inquiries.

"It really was a needle in a hay stack, [finding] the company that had since dissolved but was based in Genoa," Mr Albanese said.

"There was a box in an old warehouse — most of it had been destroyed — but the box actually had the workplace details and the address of my father ... and he was living at the same address many years later."

Mr Henderson told Ms Sherry of the find, who rang Mr Albanese.

"It's a moment I'll never forget," he said.

"I was in the Commonwealth Parliamentary Offices, I was about to chair a dinner of the Australian Transport Council.

"I got this phone call just as we were about to leave and she — it was very short conversation — she said 'we've found him', and it took my breath away because I didn't think that would happen."

He opened his arms to me and we embraced

Anthony Albanese (left) with his wife Carmel Tebbutt (centre), father Carlo (right) and son Nathan (front) in Italy 2011 ( Lisa Golden )

Now, Mr Albanese faced the dilemma of how to approach the man he believed to be his father.

"I knew that I had to, even if it meant knocking on the door, I knew I had to pursue it then," he said.

"It was very much a physical need in my gut that I needed for that to happen."

Once again, Mr Albanese was able to pull some strings through contacts, this time at the Australian Embassy in Rome.

"As well as knowing Amanda Vanstone ... my second cousin happened to work at the embassy [and] was in charge of the international visits at the embassy," Mr Albanese said.

"So we wrote, essentially, a letter to the family saying that I would be visiting and that I was the son of Mary Ellery, the late Mary Ellery, her maiden name, and that I would like to meet Carlo."

Not knowing Carlo Albanese's circumstances or how he would be received, he didn't mention anything about being Carlo's son.

"A friend of what I now know as my brother was a lawyer and she made contact and said that she would be happy to meet with us," Mr Albanese said.

"I arrived in Bari and then travelled up to Barletta, that's very close, on the Saturday and we met."

"Then I told her the story. She immediately responded very positively. I made it clear that I didn't want anything except to meet Carlo, who I thought was my father, that I wasn't there to ask for money or inheritance or anything else, I just wanted to meet him."

The lawyer arranged for a meeting the very next day.

Mr Albanese went to her office and waited until there was a call confirming that Carlo would be there in an hour.

"I went and had a good scotch at a local bar ... it was almost overwhelming and then I went on a walk by myself.

"I was very emotional. It was a big deal, it was a big moment in my life."

Then Carlo Albanese arrived.

"It was extraordinary.

"The bell rung ... and the door opened, he walked in and opened his arms to me and we embraced.

"It was quite — it was incredibly generous of him, I think, and it was a very poignant moment.

"He immediately said that, yes, he knew my mother and understood the circumstances.

"So, given that he ... he married the woman, as his wife, as he had told my mother he would, and had been with her ever since, it was remarkable, I think, the generosity with which he responded."

Carlo also brought along his son and daughter.

"All of a sudden, with the exception of my son Nathan, the three closest blood relatives to me, in the world, who I'd never met before were standing in this room and we sat down and conversed for about an hour and a half.

"It's hard to put into words ... how I felt. It was just completely overwhelming.

"I felt a connection to them and I felt like a gap had been filled, the fact that there was no doubt either or no questioning was a great sense of relief."

Mr Albanese showed the photo his mother had kept of Carlo attending Maryanne and her companions aboard the ship decades earlier.

"The photo that we had used to identify him, he had a copy of that photo all those years later as well."

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 10 minutes 49 seconds 10 m Anthony Albanese's long-held family secret

Farewell and closure

Over the following years, Mr Albanese and his Australian family made regular visits to Italy discovering the family they never knew existed.

But Carlo was ill.

During one of the most tumultuous periods in Australian political history — the lead up to the 2013 election — the now Deputy Prime Minister was campaigning hard but he had one eye on Italy.

"He had cancer and was very sick during the 2013 election campaign," Mr Albanese said.

"Kevin Rudd knew that at any time I might depart for — to farewell him, which I needed to do. I needed to have closure.

"He died in January of 2014 and I was very pleased that I was able to have that final engagement with him. He was lucid and he told me — the last conversation we had was that he was glad that we had found each other."

Mr Albanese first revealed the discovery of his father in a new biography, Albanese: Telling it Straight by journalist Karen Middleton.