The baby, due mid-July, will be third in line to the throne after Prince Charles and Prince William and is the latest in a run of royal and sporting events such as the Olympics and the Queen's Diamond Jubilee in the UK.
"This is a good news story and there really is no downside. With the birth coming in July, people will have time to get involved, and that means additional spending," Joshua Bamfield, director of the Centre for Retail Research (CRR), said in reference to a new report forecasting the retail scenario for the country in the coming months.
Prince William married Kate Middleton in April 2011 and the Queen marked her Diamond Jubilee in June last year, closely followed by the London Olympics.
All events were marked by high tourist figures and consumer spends.
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According to a 'Daily Telegraph' report, Bamfield forecast 4.8 million people would spend 62 million pounds on alcohol and 25 million pounds on food for parties.
He expects 156 million pounds to be spent on commemorative china and other collectables, toys, books, DVDs and media.
"One of the biggest factors will be the unintentional royal brand endorsement. The 'Kate effect' has already taken the fashion world by storm... And this trend will follow for the infant's baby grows, rattles, first bike and so on," Bamfield added.
Richard Cope, trends director at market researcher Mintel, also expects the Duke and Duchess' baby to have a positive impact on consumer spending, which only ticked up 0.1 per cent between January and March this year.