Martin Lewis said he was left in a "cold fury" after hearing a retired teacher's experience with a Bitcoin scam which had used illegally Bear Grylls' face.
Theresa told ITV Good Morning Britain viewers she had "invested" in Bitcoin after seeing an advert online, but ended up tens of thousands of pounds in debt.
She said she saw the advert online with Bear's face and decided to invest, initially lured in with £250. She was given a fake advisor, who lied about how well her investments were doing, The Mirror reports.
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Gradually, she invested thousands in the scam and when she wanted to take the money out, she was charged with an additional fee and had to borrow money from a friend in order to do so.
"They were just milking you for money and you couldn't withdraw," host Susanna Reid said. "The thing is, not only did you lose a huge amount of money - £125,000 in all - but it's damaged the bond you have with friends and family, which must have had a massive impact on your support system and your mental health."
Theresa replied: "Yes, absolutely. The friend that lent me the money - I think it affected our relationship after. It's very hard, with my daughters it was hard because they tried to advise me."
MoneySavingExpert founder Martin said: "I'm sitting here in a cold fury, if I'm honest, as I listen to this."
Addressing Theresa, he said: "Can I just say to you - you said it was astonishing. It's not for me - I had someone lose £100,000 this weekend, I had someone lose £200,000. I cannot tell you how many people there is in your position.
"But you are so brave because people won't talk about it because it damages their financial health and their mental health when they talk about being scammed and you are wonderful for coming on to talk about it and spread the message.
"So a personal thanks from me. It's really appreciated."
Martin has frequently warned about the scams and in 2018 issued High Court proceedings against Facebook for defamation after 1,000 scam ads abusing his name or image appeared on their website in a single year.
He settled the lawsuit after Facebook agreed to donate £3m to an anti-scam charity. The social media site has also since launched a new scam ads reporting button.
Theresa has managed to get half of the money back after her bank helped, but is still trying to get the rest.
