Married couples could be missing out on more than a thousand pounds says Martin Lewis.
The Money Saving Expert appeared on This Morning on Monday to give viewers some more money-saving advice.
One of his important pieces information was the couples may be able to claim up to £1,150 because of marriage tax allowance.
Martin said on the ITV show: "I've spoken about marriage tax allowance many times before. This is for those who are married or in a civil partnership - living together unfortunately doesn't count.
"What this says is, if you are a non-tax payer married to a 20 percent basic-rate taxpayer, the non-taxpayer can give 10 percent of their tax-free allowance to the taxpayer.
"This year that's £1,250 which means they have £1,250 they can earn without paying tax on it. They would have paid 20 percent so it's a gain of £250.
"This means £1,250 of income they were taxed on at 20 percent is now tax-free – a £250/year gain done via altering your tax code.
"There are still over 2 million couples who are eligible and haven't claimed."
He then continued: "You can back claim that four years. Which means if you were eligible for the last four years, as two million who haven't claimed are, you're entitle to £1,150 in cheques."
But you need to do this by April 5.
This is because from April 6 we're in a new tax year and the 2015/16 tax year disappears which means you can no longer claim it back.
To apply yourself, the non-tax payer must be the who claims and can be done so on the Gov.co.uk website.
