Dubbed 'The Impulse Diaries', the campaign features a "behind the scenes" peek into the girls' lives and coincides with the launch of their second album.
The TV content, which involves a sponsorship package on Channel 4, will show the girls in various settings, including a hotel room, a tour bus and backstage before a gig. This will first air on October 23.
The campaign hub is a dedicated Facebook page, where The Saturdays will post exclusive content and invite users to interact by posting their romantic stories to be in with a chance of winning prizes.
The Facebook site will be supported by activity on MSN, online PR, and a series of print ads.
Impulse said the five girls were picked as partners because "they embody the fun, flirty spirit of the brand".
Estelle Alty, senior brand manager, female deodorants, Unilever, said: "Working with The Saturdays is a fresh and exciting new approach for Impulse.
"We think The Saturdays will really engage with the brand and make it relevant and exciting for our consumers.
"Throughout the campaign we will be creating lots of exclusive and exciting content that will help bring the brand to life and remind young women that Impulse body spray can have a place in their daily beauty routine."
Last week it was revealed that Polydor Records was launching a social networking site for the launch of The Saturdays' second album.
Features of the site include profile pages on each member where they offer fashion tips to fans.