The Children's Society is using Forster to promote its new campaign to draw attention to the problem of runaways.
The Make Runaways Safe campaign was launched last week with a report stating that more than 100,000 children run away from home or care every year, placing them in 'grave danger' and at risk of physical abuse and sexual exploitation.
The campaign will raise awareness of the dangers facing children who run away from home.
Forster helped shape the campaign and will continue to work on the PR and lobbying drive in the coming weeks. The agency has also been asked to create a dedicated campaign microsite, which is planned to go live in August.
Children's Society Campaign for Childhood director Elaine Hindal said: 'Children as young as eight are running away from home or care and massive numbers of children remain hidden from view and are not reported to the authorities.
'We've worked with Forster to create a campaign to raise awareness about the issues affecting young runaways and for a national safety net to be put in place for every child who runs away.'
Forster board director Athena Lamnisos said: 'We hope that Make Runaways Safe will succeed in drawing the public support that it deserves and result in the changes to local and national policy that the Children's Society is aiming for.'
The report reveals that children's disappearances go unreported in two-thirds of cases.
According to the report, the average age of young runaways involved in Children's Society projects has dropped from 13 or 14 to between 11 and 12.