The campaign – which launches next Easter – will focus on promoting its latest TV brand, the pre-school animation show, 'Toby’s Travelling Circus'.
'Toby's Travelling Circus' first appeared as part of Channel 5's 'Milkshake!' programming in September, and has been commissioned for a second series to air in 2014/15.
The show recently led to an exclusive multi-book publishing deal between Komixx and Random House Children's Publishers UK (RHCP).
The multi-book deal for 'Toby's Travelling Circus' includes picture books, reader books, activity books and annuals.
RHCP has secured both print and digital publishing rights, including eBooks in all languages, and will work closely with Komixx and other licensees on a launch programme for 2014.
The appointment of the7stars marks the first appointment of a media agency by Komixx.
Andrew Cole-Bulgin, joint chief executive and head of Film and TV, Komixx Entertainment, said: "'Toby’s Travelling Circus' has proved to be a huge success and with the commissioning of a second TV series by Channel 5 'Milkshake!'. And with the latest publishing deal with Random House, we felt that next year was the right time to give the brand a strong media push.
"The7stars' experience in the entertainment sector and their focus on providing a highly targeted media strategy, means they are perfectly placed to help us reach the right audience and bring the success of Toby to an even greater level."
Sam Farrand, account strategist at the7stars, said: "What Komixx does really well is not just creating programmes, but going one step further to create brands with enduring global appeal.
"The fact that a media entertainment company is working with a media-buying agency just shows how dedicated they are, not just to commission shows, but to bring their characters and concepts to life – and Toby is a perfect example of this.Follow @nickbatten2