Retail guru to lead an independent review to identify what the Government can do to tackle the issue of empty shops and develop more prosperous and diverse high streets.
Ms Portas will present her findings to the Prime Minister, Deputy Prime Minister and Ed Davey this autumn.
Her task is to advise the Government on how it can address the problem of vacant shops, increase the number of small and independent retailers in local towns and prevent the proliferation of 'clone towns', dominated by large retail chains. The review is also set to look at adopting new business models for the high street that better suit the needs of today's modern shoppers.
In order to gather information for the review, Ms Portas will visit a number of town centres and engagement events across England.
She explained: "With our high street vacancy rates doubling over the last two years, the need to take action to save our high streets has never been starker. I am calling on businesses, local authorities and shoppers to contribute their ideas on how we can halt this decline in its tracks and create town centres that we can all be proud of."
Announcing the move today, Prime Minister David Cameron said: "I am delighted that Mary Portas has agreed to take on this review and I am confident that her straight talking, no nonsense approach will help us to create vibrant and diverse town centres and bring back the bustle to our high streets."
The British Retail Consortium (BRC) believes the review is a "positive step" but only if the emphasis is on "support-for-all" rather than penalising successful retailers.
"The Government is right to recognise the future of our high streets cannot be left to chance but it must take a positive approach that supports retailers of all types and sizes. Independents are a vital part of an attractive retail mix but so are the big names. Ultimately it's customers who have the power in retailing through the shopping choices they make. This review should not seek to restrict that choice by making life harder for any particular category of retailers."
The trade association's own high street rescue plan sets out a range of priorities, including keeping business rates down, deterring crime and providing good, affordable parking.