Angry Birds maker Rovio has secured the rights to develop and publish games based on the Moomin franchise. 

The Finnish studio has signed a long-term partnership with Moomin Characters and Gutsy Animation that will give it the rights to create Moomin titles for "any platform" and the exclusive rights to develop mobile games based on the popular multi-media franchise.

The deal will also see Rovio become a minority shareholder in Gustsy Animations -- known for creating the Moominvalley animated TV series -- through an equity investment of €2.5 million ($3 million) and a convertible loan of €2.5 million ($3 million). 

Rovio explained the Moomin franchise, which focuses on a family of rotund hippo-like creatures with endearingly large snouts, will help diversify its portfolio. It also pointed out the series has become very popular in Japan, which it noted is "one of the world's largest gaming markets."

"This partnership will diversify our IP portfolio, which is a key step in our consistent growth strategy," said Rovio chief exec Alex Pelletier-Normand. "Rovio’s first Moomin game, based on the original story and world created by Tove Jansson, and inspired by the Moominvalley visuals, is already being developed and we expect it to reach soft launch later this year."