Mrs Brown has been at her husband's side ever since he called the general election earlier this week, even canvassing voters by telephone.
Gordon Brown said the 'love of his life' had chosen to take on a high-profile role and they enjoyed 'going around the country together'.
The Prime Minister's aides have denied that there is a thought-out strategy for Sarah Brown in Labour's election campaign.
Portland PR partner George Pascoe-Watson said that the move 'can't do him any harm'.
'In general, having the wife on board for your election campaign doesn't do harm in most cases. It's a positive thing for his image,' said former Sun political editor Pascoe-Watson.
But Mandate Communications head of digital Mark Pack said it was a risky strategy.
'The reason they're doing it is it gets you extra press coverage, but at the same time the media tend to be reluctant to ask tough questions. But there's a risk there that they could do it too much. I would say the risk is greatest for the Conservatives as Samantha Cameron is doing more solo stuff than Sarah Brown.
'The risk is that if something happens in their private lives, if you put yourself up in front of cameras it's hard to say something is private.'
Luther Pendragon director Mike Granatt said she was Brown's 'only weapon' to convince voters that he relates to real families.
'Gordon Brown is Labour's biggest asset and its biggest liability. The voters know he's a great clunking manager, but they want a PM who understands what real people will face in the economic famine to come,' said Granatt.