Shine will be responsible for creating an integrated digital campaign, covering search, video seeding, social media outreach, digital PR and campaign analytics.
Only Men Aloud!, which features 18 Cardiff-based singers, will release their new album through Universal Classics and Jazz on November 24.
The group signed a multi-million pound deal with Universal in September after winning the BBC's search to find the nation's favourite choir.
Chris McCafferty, director of Shine Digital, said: "Only Men Aloud! built up a strong online fan base throughout 'Last Choir Standing'.
"We'll be targeting these communities and wider groups to help make the album a massive hit."
Shine Digital is a newly formed sister company to Shine Communications, specialising in digital communications.