Lorraine Kelly was left speechless after a guest told an 'extraordinary' story.
Donna McLean appeared on ITV's Lorraine on Wednesday's broadcast on February 2.
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She explained to Lorraine how she fell in love with a man that went by the name of 'Carlo Neri' who said he was an activist.
Donna who is originally from Scotland, was in a relationship with him for two years from 2002, and got engaged on Hogmanay after just three months of dating.
But her life was thrown up in the air as she discovered 'Carlo' was in fact an under cover policeman, keeping an eye on her friends involved in left-wing activism.
Donna had met the seemingly perfect charming Italian at an anti-war protest after the news of the Iraq war broke out.
"You had no idea he was there to infiltrate?", Lorraine asked.
Donna shook her head and explained how she thought he was her soulmate, how quickly she fell for him-without knowing he was living a double life with a wife and family "just down the road".
She even discovered that his wife was pregnant while they were together.
While Donna wasn't particularly politically engaged, her friends were.
Donna was a nurse working managing a drug treatment service for homeless people, a trade union rep and just went to the 'odd protest march'.
After they broke up, she read a book about the 'Spy Cop' scandal, Undercover by Rob Evans and Paul Lewis
Donna told Lorraine how the hairs on her neck stood up as she realised she had experienced similar things as the activists in the book.
Then in 2015, she received a message from an old friend who simply said, "I need to talk to you about Carlo".
The whirlwind romance had been a lie, Carlo was an undercover police trying to get information from the activist groups.
Any flashy gifts Donna may had received, would have all been put on his expenses, she adds in the Guardian.
After speaking to Rob Evans, she decided to go through the legal process and take him to court but admitted to Lorraine Kelly how mentally difficult it was.
Unlike counselling where things are gradually processed and discussed, she said: "Everything single aspect is scrutinised."
Donna might have to see 'Carlo' again in court, but while she admitted she wouldn't know what to say to him, she told Lorraine that no matter what he said, she wouldn't believe a word.
The ITV presenter asked how could she trust anyone again after going through that.
Donna said: "The court case took five years, I've come out of it and I trust people as much as I did before".
"I went through a process", she adds.
Donna has now went on to write a book, 'Small Town Girl' that she admits happened by accident.
She explained she wanted to write everything down to process it and understand what happened afterwards.
Since Donna has uncovered the truth about her former 'soulmate', she has gone on to campaign and raise awareness.
According to reports there have been 139 police officers have spied on more than 1,000 political groups since 1968.
