Finnish software firm Rovio, well-known for the popular mobile-phone game "Angry Birds," has secured $42 million in a Series A round of funding co-led by Accel Partners and Atomico Ventures.

Skype co-founder Niklas Zennstrom, who started Atomico Ventures, is joining Rovio's board of directors. Capital-venture firm Accel Partners has earlier made investments in AdMob, Facebook and Groupon.

The Finnish firm said the recent funding would facilitate its strategic expansion. The firm has plans to launch Angry Birds on more platforms this year.

Rovio's mega-hit game Angry Birds, which allows players to catapult birds into fortresses built by egg-stealing pigs, boats of its more than 40 million monthly active users.

In addition, the sales of Rovio’s Angry Birds lush toys recently surpassed two million units, certifying the popularity of the birds.

Angry Birds was originally rolled out in Apple's App Store in December 2009. Gradually, it moved to the other major smartphone platforms, with RIM’s BlackBerry the only major exception.