IPTV channel Zattoo has called in Firefly after a competitive pitch.
The agency will provide UK consultancy ahead of Zattoo's launch this spring.
The channel is already a success in mainland Europe, with more than two million subscribers so far.
Zattoo has signed up BBC One, BBC Two, Channel 4 and Five, among others.
In the weeks leading up to Zattoo's UK launch, Firefly will be focusing on the blogging community and early adopters willing to try Beta websites.
The London agency will then launch the website to the mass market, using both traditional and online media.
Firefly has also been briefed to target trade titles in efforts to drum up advertising and create interest among broadcasters in the Zattoo platform.