The Duchess of Cambridge has been moved by the story of a recovering alcoholic mother who has turned her life around with help from a charity of which Kate is patron.
Anna Elston, 43, told how her three young sons were taken into care at the height of her drinking more than eight years ago but today she trains volunteers to give empowering talks to teenagers.
Kate met Ms Elston when she gave an inspiring speech about her life story, the day after she and fellow graduates received their foundation or degree certificates in addiction counselling.
They had studied at the Centre for Addiction Treatment Studies in Warminster, Wiltshire, run by the charity Action on Addiction which has the Duchess as its patron.
Ms Elston works as a co-ordinator for the Amy Winehouse Foundation's resilience programme in Bournemouth - a drug and alcohol awareness and prevention initiative for secondary schools.
In her speech to Kate and her fellow graduates, she said: "If you had told me eight years ago that I would obtain a first-class honours degree in addiction counselling and be asked to deliver a speech to the Duchess of Cambridge, my mum, my three sons and about 100 other people, I simply would not have believed you.
"I didn't believe a lot of things back then, when I was entrenched in active alcoholism. I didn't believe that I could stay sober for more than one day."
She described how, at the time, the youngest of her three sons - Jack, 13, Eddie, nine, and eight-year-old Dylan - was in neonatal intensive care "fighting for his life" after being born prematurely at 25 weeks, weighing 1lb 2oz.
The boys were taken into foster care for a year but Ms Elston later won the right to have them back.
After her speech, she said "I should be dead, if there weren't people there for me".
Speaking about the Duchess's reaction, she added: "She looked touched."
During the visit, Kate chatted to some of the teaching staff before joining a group of addiction counselling graduates.
More than 200 students have graduated from the facility, which provides foundation and honours degree programmes accredited by the University of Bath.
Many have personal experience of substance abuse and other addictions or have a family member who has been an addict.
The Duchess told Derrick Anderson, programme director at the centre, that those studying for degrees must get satisfaction out of being able to use their personal experiences of addiction.
She said: "It must be so powerful for them talking to patients who have gone through similar things.''
During the visit, Kate was also given an update about a national programme run by Action on Addiction which takes a whole-family approach to tackling substance misuse, and she privately met families taking part in the initiative.
She told Mr Anderson: "I think the holistic approach, getting the whole family, is so important - it doesn't affect just one person.''
When she sat with foundation and degree graduates, the Duchess congratulated them: "It's such a positive story for all of you."
Martha Bache, 30, who is in recovery from prescription pill addiction, said: "I recognised I had a problem and wanted to do this course. I was interested to learn and help people and support people whatever the problem."
Ms Bache, who works with hoarders, some of whom might suffer with mental health issues such as OCD, said she recognised in Kate the same skills that they have been learning as counsellors.
The 30-year-old said: "She is so lovely and friendly. That is what we have to do as counsellors - we give people a voice and some tools. And the fact is she can talk to us in the same way.
"She's incredibly warm - she's a human being who inspires me. She shows empathy, the same empathy that I am aspiring to have."
Based in a former manor house since 2008, the Centre for Addiction Treatment Studies is attempting to raise the standards in the field of addiction treatment by training counsellors to a higher standard.
In the past the specialism has been criticised for its poorly trained workforce who are sometimes seen as ill-equipped to deal with the needs of addicts.
Kate has visited a number of Action on Addiction's services before but this was her first official trip to the centre to meet course tutors and examiners training the next generation of counsellors.
David Gabriel, 49, from Frome, has completed a full-time foundation degree in addiction counselling after changing career when a medical problem forced him to give up a 25-year career as a roofer.
He now works for the Exeter Drugs Project but, like a majority of students, it was a personal connection with addiction that got him involved in the field as his parents were both alcoholics.
Mr Gabriel said: "We're going to the best college, we're better trained then our bosses because this course is so evidence-based.
"I'm often called into meetings with my boss because of my experience."
After the speech by Ms Elston, Kate posed for a picture with all the centre's graduates.
Also among the guests was Duran Duran bassist John Taylor, who is a supporter of Bath University's links with Action on Addiction's centre.