However, he remains the creative director at Channel 4, in which role he oversees the network's creative services departments and 4Creative, the in-house creative agency behind the channel's on-air brand.
Commenting on the signing, Polly Cochcrane, the channel 4 director of marketing, said: "We're delighted Brett has been given this opportunity. It's great for him and also great for 4Creative.
Channel 4 has a policy that allows staff to take unpaid leave to pursue personal interests."
Foraker, 37, joined Channel 4 from Turner Broadcasting. He was responsible for the recent Jamie's School Dinners campaign and the "faces of four" campaign in which stars of Channel 4 programmes, such as Teri Hatcher and the Osbournes, answer questions including "what was your first car?" and "what's your favourite swear word?"