Prepare to feast your eyes (and ears!) on the men of University of Oxford's all-male a cappella group, Out of the Blue, covering Mariah Carey's 'All I Want for Christmas Is You.'

We're pretty sure that even the Grinchiest of Grinches would crack a smile (or several) while watching the vocal group's festive, happy-go-lucky vid. The guys not only look great, dressed in both suits and their finest holiday attire -- but they sound amazing, infusing Mariah's classic Christmas hit with enough perfect harmonizing to give you ALL the feels.

But the best part of all is not the song, not the group, and not even in the video -- it's the fact that Out of the Blue's cover is a charity single, and all proceeds go to benefit the UK's Helen & Douglas House, the world's first children's hospice. Download it here, and watch Out of the Blue's cover of 'All I Want for Christmas Is You' in the video above!