Christmas carols, dancing, jokes, and cussing — leave it to Jimmy Fallon and Justin Timberlake to pack all the fun into their Saturday Night Live promos! The hilarious duo teased tonight's episode with a few LOL-worthy moments. The show will find Jimmy returning to the SNL stage as host and Justin rocking the mic as the musical guest. Jimmy was sans Justin in his first round of promos, but that didn't stop him from singing JT's "Mirrors" with Kenan Thompson in the snow. Tune in to NBC to find out if Jimmy and Justin will give us an early Christmas present with a holiday-themed episode of their classic sketch, "The Barry Gibb Talk Show."