The girl group sang a rendition of 'I Will Wait' in the BBC Radio 1 Live Lounge, while promoting the release of their own single 'DNA'.
Little Mix performed a stripped-down version of the track and were accompanied by strings, guitar and a piano.
The group's new single 'DNA' is available to download now, while their debut album of the same name follows on November 19.
The collection will feature their recent number one track 'Wings', as well as a collaboration with TLC's T-Boz.
Listen to Little Mix cover Mumford & Sons' 'I Will Wait' below (at 3 min 27 secs mark):