The broadcaster is one of five customers that TNT Mail has signed in its first three months of operations. It is joined by Booker, Express Gifts and Caudwell Communications, adding to the service's 20 existing clients.
Kevin Trever, procurement manager for marketing and print at Sky, said: "We have been extremely impressed with TNT Mail's service. Over the last three months they have met all our expectations and offered an effective two-day service for a sizeable piece of business."
TNT says it is now handling 1m items a week, since an access agreement it has with Royal Mail went live in August last year. It expects to handle more than 200m items this year.
If you have an opinion on this or any other issue raised on Brand Republic, join the debate in the .