Lewis, dubbed the Money Saving Expert, will start the week with Reid and they will offer viewers the most up-to-date information while also “holding politicians to account” every Monday in September.
Discussing the importance of the show in the current economic climate, Reid said Lewis is the “hero we all need right now”.
She told the PA news agency: “It is the one thing that everybody is talking about, thinking about, worrying about, concerned about.
“People need answers and what I think is so perfect about Martin being on the show on a Monday is that even if the politicians can’t provide answers, Martin always has suggestions, always has solutions.
“I know that he personally feels like he is running out of options, but at least you know that with Martin you’re not just getting somebody who is going to ask the right questions but he’s also got all this information at his fingertips.
“He has a very analytical mind, and he wants to go out of his way to help people. So it’s the perfect person at the perfect time.”
Reid, 51, who was praised for her GMB interview with Boris Johnson, particularly for her questioning on the cost-of-living crisis, said there is an open invitation for the next prime minister to appear on the show.
She said: “We are at heart a current affairs show news programme, we have that kind of viewership, we always want to hear from those in charge.
“I personally send that invitation to whoever the next prime minister is, as soon as they are in position, because our viewers will want to know exactly what their plans are and we will want to interrogate them to make sure it all stands up.
“Once again, Martin Lewis is the perfect person to do that.”
Lewis, 50, said that if he had the opportunity to interview the new prime minister, his aim would be to “analyse, explain and interrogate the package that has not been announced yet”.
He told the PA news agency: “It mirrors what we had in the pandemic. The impact on people’s home lives by the cost-of-living crisis is a mirror to the impact the pandemic had on many people’s home lives.
“Sadly, the only way to get through this particular crisis for millions of people who are the poorest, most vulnerable will be through Government help.
“So it’s important we hear from the people responsible for making decisions, why they are making the decisions that they’re making and how they think it will operate.”
Lewis said he views his role as “two-fold” during the crisis.
“It is both feeding back the public view to the politicians, which is something that I did with (then chancellor) Rishi Sunak during the pandemic, and also trying to explain to the public exactly what measures and help is available,” he said.
“Where that help isn’t sufficient, trying to push back whether in private or in public to make sure the help is there that is needed.
“We need to be under no uncertain terms, a lot of help is needed for a lot of people.”
Rishi Sunak or Liz Truss will be named the new prime minister on Monday following a vote by Conservative Party members, after Boris Johnson resigned in July.
Martin’s Money Mondays airs from Monday on Good Morning Britain at 6am on ITV & ITV Hub.