Colbie Caillat and Gavin DeGraw -- 'We Both Know' -- New Song

Summer tour partners Colbie Caillat and Gavin DeGraw have worked together once again to finish a song they wrote together months ago. The duet, 'We Both Know,' was written on a bus ride months ago and is expected to be featured in the upcoming Nicholas Sparks movie, "Safe Haven."

The mid-tempo tune has a poetic tone and a beautiful sound, backed up with a piano track and strings. In a very soulful manner, the two share many vocals and match their harmonies very effectively. The ballad seems perfect for a Sparks film and sounds quite powerful, especially towards the end of the song. The final chorus wraps up the sound and meaning of the song nicely as the two sing in harmony: "We both know our limitations, that's why we're strong. Now when we spend some time apart, wheeling each-other out of the dark, cause we both know."

Caillat and DeGraw recently premiered the song in Los Angeles. It is unclear when each artist will release the track or on what album, but the two have said they plan on writing more material together. For now, fans can listen to the single on AOL Radio's New Pop First.