Martin Lewis appeared on This Morning with some urgent advice for those aged between 18 and 40.
The MoneySavingExpert founder was answering the public's questions and issuing his usual finance tips and tricks.
One woman rang to ask about the differences between the Help To Buy ISA and the Lifetime ISA.
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She said she had a Help to Buy ISA and wasn't sure if she should transfer the money over into a Lifetime ISA.
While Martin advised her to stick with her current ISA account, he issued a warning to future homeowners.
Recapping, Martin said on Twitter: Tip for 18 to 40-year-olds. If you hope to buy a home in the next five to 10 years, put £1 in a LISA now.
"These give first-time buyers a 25% bonus (up to £1000 a year) on their savings after its been open one year.
"So open with £1 now to start that clock, so it's usable when needed."
What is a Lifetime ISA?
You can use a Lifetime ISA (Individual Savings Account) to buy your first home or save for later life. You must be 18 or over but under 40 to open a Lifetime ISA.
You can put in up to £4,000 each year, until you’re 50.
The government will add a 25% bonus to your savings, up to a maximum of £1,000 per year.
You can hold cash or stocks and shares in your Lifetime ISA, or have a combination of both.
When you turn 50, you will not be able to pay into your Lifetime ISA or earn the 25% bonus.
Your account will stay open and your savings will still earn interest or investment returns.
