Well, happy holidays. (YouTube)

Nothing says merry Christmas like seeing The Rock ... singing "Here comes Santa Claus" ... in a onesie on Live with Kelly and Michael.

Fair warning: You can't un-see The Rock swiveling his leg Elvis-style, but gather 'round the computer, pour some healthy servings of eggnog and call it quality family bonding courtesy of Dwayne Johnson. Those cherished opportunities simply don't come around but once a year. 

Here's the entire Christmas kareoke smackdown challenge: