Packing on the PDA on the red carpet was Bachelorette Rachel Lindsay and her chiropractor fiancé Bryan Abasolo, who plan on walking down the aisle next year.
Meanwhile, British belters Ed Sheeran and Sam Smith showcased their divergent taste in fashion at the Los Angeles event.
Next year, the twice-rehabbed starlet - who's five years sober - kicks off her 20-date co-headlining Demi x DJ Khaled Tour on February 26 at the Viejas Arena in San Diego.
Also headlining Friday's Jingle Ball was Halsey, who swapped her extremely unflattering denim ensemble for a skimpy Prada outfit onstage.
Bella Thorne kicked up her silver platform heels while drumming up publicity for her 2018 romance Midnight Sun alongside onscreen leading man Patrick Schwarzenegger.
On the mic: The 23-year-old Grammy nominee (born Ashley Frangipane) belted her new single Him & I in a yarn bra-top, glittery hotpants, and pop star cliché thigh-high boots selected by stylist Maeve Reilly One Direction's Liam Payne and Niall Horan represented their UK boyband, separately, while clad in casual wear.
There's no telling if the song really is about one of these lucky ladies but it's always fun to try and guess what exactly is running through Niall's head.