Attenborough assumes the brief from Consolidated Communications in September following a three-way pitch last month (PRWeek, 28 June).
Consolidated has run the account for eight years but declined to repitch for the work.
Attenborough reports to Blockbuster communications manager Tim Fairs, who oversaw the review.
Agency managing director Nick Attenborough said: 'We'll run a proactive news service, getting details of what they're up to into the press, and capitalising on their charity work through the Starlight Children's Foundation.'
He added that final details of the account were still being ironed out ahead of the start of the work next month.
Attenborough - who said speculation the account was worth 'sizeable six-figure fees' was 'in the ballpark' - and agency director Merrigan Twelves head the account.