Watch Dave Grohl, Kristen Bell Perform Metallica, 'Frozen' Mash-Up

Foo Fighters frontman dressed as David Letterman during 'Jimmy Kimmel Live!' Halloween cover of "Enter Sandman," "Do You Want to Build a Snowman?"

Dave Grohl and Kristen Bell teamed to perform a mash-up of Metallica's "Enter Sandman" and 'Frozen' song "Do You Want to Build a Snowman?"

Foo Fighters' singer Dave Grohl recruited Kristen Bell on Tuesday's Jimmy Kimmel Live! to perform a bizarre Halloween mash-up of Metallica's classic "Enter Sandman" and Frozen ballad "Do You Want to Build a Snowman?"

Grohl, guest-hosting the show for an absent Jimmy Kimmel, initiated the cover while interviewing Bell. The rocker, wearing a shockingly realistic David Letterman costume, told the actress how much his three daughters love "Do You Want to Build a Snowman?" from the animated 2013 movie. "It's kind of the biggest deal to my kids," he gushed. "If I were to jam a song with you, I would become the coolest dad in the world."

Bell, decked out with chest hair and massive mustache as Tom Selleck circa Magnum P.I., excitedly agreed, jumping behind the mic to croon in the spotlight as Grohl mouthed the lyrics from behind the desk. Then the Foo Fighters frontman sprinted to reach the drum kit, joining house band Cleto and the Cletones for a morphed metal version of the song, which bled into "Enter Sandman."

"I tuck you in, warm within, keep you free from sin/ Until the snowman he comes," Bell snarled, altering the lyrics to the 1991 track.