Video: Mumford & Sons Debut New Song, "Ghosts That We Knew"

Folk-rockers Mumford & Sons recently made an appearance on Philadelphia's Radio 104.5 FM, where, as a special surprise, they debuted a brand new song called "Ghosts That We Knew." You can watch video from the performance below.

Of course, this isn't the first new track Mumford & Sons have debuted live during a radio performance lately, as earlier this year they debuted a new song, tentatively titled "Home," during an intimate concert for a Colorado radio station.

Mumford & Sons are expected to release the follow-up to 2010's Sigh No More sometime in 2012.