The pitch, for the Department for Work and Pensions, saw them beat WWAV Rapp Collins, Ogilvy & Mather and Publicis to the task.
It is thought that the spend on above- and below-the-line work in the first year will be almost evenly split. Media remains with PHD.
The Government is running the campaign to raise awareness and clarify details about the pension credit before its full public launch. The pension credit is aiming to reward pensioners who have saved extra cash or who made provision for a second pension.
DLKW has already established a foothold with the DWP with its Pension Guide work on social security, which uses television spots featuring talking sheep dogs.
It is the first time DLKW has jointly pitched for COI work with a below-the-line agency. However, it has co-pitched with media agencies in the past, notably Naked in the successful COI pitch for the Department of Health's adult sexual health work.
DLKW and DraftWorldwide have worked together previously on accounts for the Financial Times and Birmingham Midshires.
The first work is earmarked for an autumn debut, with TV, press, direct marketing and digital executions.