Over the past year, Jens Lekman and Annika Norlin have been sending each other songs every month as part of a project called Correspondence. Jens explains:

A little over a year ago, me and Annika Norlin did what many friends who see each other too seldom do - we promised to get in touch a little more often.

We called the project CORRESPONDENCE.

These were the rules:

* One letter a month, in the shape of a song. Six songs each, twelve in total.

* Only one instrument could be used for each letter. The songs were attempts to impress each other, make each other laugh and cry. They contained our thoughts about things that occupied our minds at that very moment.

The songs include one by Jens from July called "Revenge of the Nerds" which is, in part about rewatching that 1984 hit film for the first time in a long time:

You can listen to that and all the songs in their Correspondence series, including "Silent Night" which was released today, and read a little more about it from Jens, below.