No, your eyes are messing with you, that is actually Dave Grohl dressed up as David Letterman and Kristen Bell as Magnum P.I. and if you think that's where the weirdness ends, think again.

The Foo Fighters frontman was Tuesday night's guest-host on Jimmy Kimmel Live and seeing as it was Halloween, costumes were called for and neither Grohl nor Bell disappointed. And because the two are musically inclined, they even teamed up for probably the most bonkers mash-up you'll hear today.

Yes, you're going to have to hear a bit of Frozen’s 'Do You Want to Build a Snowman?' for a bit but then it all kicks off and trust us, it's worth it.