The moment is captured in a Channel 4 documentary — broadcast on Thursday — as the 45-year-old charity worker, who was detained as part of a long-running dispute between Britain and Iran, marks a year since she returned home.
Daughter Gabriella, then aged seven, runs into Ms Zaghari-Ratcliffe's arms after she drops to her knees in the emotional scenes.
She sobs and speaks to Gabriella as her husband Richard, who fought a public campaign to get her freed, kisses their daughter on the head and says: “Can you remember your Farsi?”
Ms Zaghari-Ratcliffe then stands up, not letting Gabriella go, and says: “I had better kiss daddy, too, you had better kiss daddy, too.”
She continues to look at her daughter as she says a few more words in Farsi, only for Gabriella to say: “I don’t understand.”
Ms Zaghari-Ratcliffe replies: “You are so beautiful.” Gentle laughter can be heard as Gabriella says: “I know.”
During this time, while they are standing, Mr Ratcliffe is kissing his wife’s forehead.
The emotional homecoming came in the early hours of March 17 last year after Ms Zaghari-Ratcliffe and another released British Iranian, Anoosheh Ashoori, a retired civil engineer, arrived at RAF Brize Norton in Oxfordshire to be reunited with their families.
Mr Ashoori was arrested in August 2017 while visiting his elderly mother in Tehran, and despite living in the UK for 20 years, was later convicted of spying for Israel’s Mossad intelligence agency and sentenced to prison for 10 years.
Nazanin Zaghari-Ratcliffe — in pictures
Amnesty International described their release and return as “the news we and their families had hoped for every day” since Ms Zaghari-Ratcliffe’s arrest in 2016. The organisation added that it came after the pair had jointly spent more than 10 years being “unjustly detained” in Iran.
The documentary tells the story of Ms Zaghari-Ratcliffe’s detention in Iran and the campaign by her husband to get her home.
The dual British-Iranian citizen was detained on April 3, 2016 by the Iranian Revolutionary Guard Corps at Imam Khomeini Airport after a holiday visit with Gabriella to see her parents.
Iranian authorities alleged Ms Zaghari-Ratcliffe was plotting to topple the government in Tehran, but no official charges were ever made public.
She landed back in Britain in March 2022 after the UK agreed to settle a £400 million debt dating back to the 1970s, allowing Ms Zaghari-Ratcliffe to be reunited with relatives.
Since her release, Ms Zaghari-Ratcliffe has been getting used to family life but also showed support for women and girls who have faced harassment and abuse from the Iranian authorities.
Earlier this month, she and her husband took part in a roundtable meeting with 10 Iranian and Kurdish women human rights campaigners which was also attended by Labour leader Keir Starmer.
The event, which was convened jointly with Amnesty International UK, focused on the role of women in the protests across Iran that followed the death of 22-year-old Mahsa Amini in police custody last year.
She died in September after being detained by the Iranian morality police for allegedly wearing her hijab incorrectly.
Ms Zaghari-Ratcliffe cut her hair as a gesture of solidarity with the women protesting in Iran following Ms Amini’s death.
Tehran has detained a number of dual and foreign citizens in recent years.
The country has been rocked in recent months by anti-government protests seen as the biggest challenge to Tehran’s authority since the 1979 revolution.
Executions have taken place of people who have been convicted of charges linked to the protests following internationally criticised trials.