THEY spent hours on set together, chatting over cups of tea and discussing life's many mysteries.
One, a mother who had endured enough pain to last a life-time; the other, an Oscar-winning actress trying to give an accurate portrayal of that mother's earth-shattering anguish on screen.
Brenda Fricker has been in more than 100 movies throughout her lengthy career, but describes Bernie Guerin as one of "the loveliest" people she had ever met.
The My Left Foot star played Mrs Guerin, who was laid to rest on January 17, in director Joel Schumacher's chilling biopic about murdered journalist Veronica Guerin in 2003.
"Looking into her eyes, you could see that part of her had died, it was extremely moving," says Fricker, as she remembers when the two were introduced during filming.
"I was nervous speaking to her when I met her at first, but she turned out to be such a lovely person, she was a delightful woman.
"It's slightly intimidating when the person you're pretending to be is there watching, but it's also helpful.
"I was away when I heard of her death, so I couldn't go to the funeral. It's very, very sad, but in one way, I'm almost pleased that she is no longer in pain.
"I'm glad that is over for her."
Fricker remains one of Ireland's most successful movie stars, and to this day is the only Irish female to claim a Best Supporting Actress Academy Award.
While she insists she has no time for the industry in its present state, dubbing it "disgraceful", she can recall perfectly the moment that she heard she was nominated in 1990.
"I almost fainted, we couldn't believe it," she says.
Now she has neither time nor tolerance for the Oscars, but the outspoken Dubliner still uses her vote.
She is one of 6,000 voting members who contribute to the fate of those seeking a coveted golden statue.
"I wouldn't go to the Oscars if you paid me, but I use the vote because My Left Foot lost Best Film by just one vote," she says.
"So you realise then that you can genuinely help somebody's career by putting in your vote if you think they're good enough.
"I get to vote in the Best Supporting Actress, Best Supporting Actor, Best Actor, Best Actress and Best Director categories every year.
"The Academy send you hundreds of DVDs and you have to spend all bloody day looking at them, making note of who's who and then filling out a form they send you, of who you think is worthy."
Although she is adamant she cannot reveal who she voted for this year, Fricker does mention later on that she would like to see Kerryman Michael Fassbender take home the prize for Best Supporting Actor for his part in Steve McQueen's harrowing 12 Years A Slave.
"Fassbender has been on such a quick rise, but it would be lovely to see him win," she says.
Last year, the former Casualty star claimed she was retiring from the big screen.
Never one to be comfortable in the limelight, she admits she feels for the next generation and how they relinquish any kind of privacy when they first step on to a red carpet.
"It's dreadful how invasive it is. But then, the younger people, they don't know anything else, do they? That's all they know – the way the industry is these days," she says.
"People my age went through a golden age of cinema, when it was a much nicer business to be in than it is now.
"You have to be very, very tough, and I got tired of being tough – it's not in my nature. I was constantly standing up for myself because you have to fight for your place."
Opinions and retirement plans aside though, the 68-year-old has stepped in front of the cameras once again – and has another project on the way.
"I'm technically retired, but I have an exemption list," she adds.
She is currently starring in writer Virginia Gilbert's A Long Way from Home, an independent feature that tells the story of a couple who realise their life-long dream of retiring to the south of France. However, their lives are changed when they cross paths with a younger couple.
"Virginia and I are twinned, we really bonded over this movie and that doesn't happen too often, let me tell you," says Fricker.
"We worked on the script together and she is genuinely a brilliant writer, she's prolific."
A Long Way from Home is part of the Jameson Dublin International Film Festival and will enjoy its general release, to selected cinemas, on February 28.
"I don't usually recommend films I'm in and I myself don't usually watch them, but this is a gem," she says.
Being a small budget production, there was no glamour on set and Fricker, who says she can't take the heat, operated without a trailer in the south of France during the height of summer.
"We all put up with any negatives because we were doing it for Virginia, we were supporting her so we didn't mind."
As for her next turn on the big screen, stay tuned.