Apocalyptica are working on a new album, but the hard-hitting cellists recently took time out for a side project of sorts. The band wrote and recorded a theme song for the latest 'Angry Birds' game, 'On Finn Ice.'

They've also shot a video for the track, which mixes a live action performance by the band with animations from the 'Angry Birds' world. The 'Angry Birds' game is meant to take place in the winter wonderland of Finland, which made Apocalyptica the perfect band to hop on as musical accompaniment.

As it states at the end of the Miika Lommi-directed clip, "This holiday season, Angry Birds are migrating north … way north." The 'Angry Birds: On Finn Ice' game is expected to surface in December.

If you like what you hear, you pick up Apocalyptica's 'Angry Birds Theme' which is currently available at iTunes. Meanwhile, be sure to set aside some time for Apocalyptica's return in 2015. The band is recording a new album with vocalist Franky Perez sitting in for the full disc. You can also look for them opening dates for Sixx: A.M. next spring.