Irishwoman Philomena Lee and actor Steve Coogan have met the Pope as they brought a campaign for the release of secret adoption files to the Vatican.
Mrs Lee's 50-year search for the son she was forced to give up for adoption in her homeland inspired the actor's latest Oscar-nominated film, Philomena.
She is now leading a campaign to help reunite families who were separated through forced adoption in Ireland.
Coogan, who wrote, produced and starred in the film, is supporting her project.
The Philomena Project calls on the Irish government to release secret records containing details of children and parents who were forced apart through adoption over the last century.
The film of Mrs Lee's struggle to find her son has been nominated for four Oscars, including best picture.
Speaking after the audience with the pontiff in the Vatican on Wednesday, Mrs Lee said: "I am honoured and delighted to have been in the presence of Pope Francis today.
"As the film portrays, I have always put great faith in the Church and the goodwill to put the wrongs of the past right.
"I hope and believe that his Holiness Pope Francis joins me in the fight to help the thousands of mothers and children who need closure on their own stories."
Coogan and Mrs Lee are due to hold a press conference in Rome on Thursday, to talk about the adoption campaign.
Mrs Lee was ordered to give up her three-year-old son when she became pregnant as a teenager in rural Ireland in the 1950s.
She was sent to home for unmarried mothers in County Tipperary.
The order of Catholic nuns who ran the home pressured her into giving up her child, who was sent to live with a family in the United States.
Despite a 50-year search that crossed the Atlantic, mother and child were never reunited and her son died several years ago.
Coogan, who rose to fame in his role as the fictional TV presenter Alan Partridge, wrote the screenplay for Philomena.
It was based on Martin Sixsmith's book The Lost Child of Philomena Lee.
The actor also portrays the journalist and author Sixsmith, who was instrumental in helping Mrs Lee to track down information about her son.
Coogan stars opposite Dame Judi Dench, who has been nominated for a Best Actress Oscar for her performance as Mrs Lee.
The Philomena Project was launched in Dublin last month, in collaboration with the Adoption Rights Alliance.
It calls on the Irish government to pass new laws that would compel state, church and other bodies to give families access to adoption records.