The two appear together onstage at the Z100 Jingle Ball to introduce Taylor Swift.
The singer performs at the Z100 Jingle Ball.
The two appear together backstage at the Z100 Jingle Ball.
The singer showcases her new moves with her backup dancers.
The singers perform her new song "End Game."
The singer glitters in gold.
The two perform their song "Good Old Days."
The two have a mini One Direction reunion.
Before the show begins, the Vanderpump Rules stars snap a few romantic selfies with their Fujifilm Instax cameras at the Jingle Ball gift lounge.
The singer admires his Christmas ornament.
The singer performs onstage.
The fashion designer walks the red carpet.
It's not Jingle Ball without a visit from Santa at the 102.7 KIISFM Jingle Ball 2017 Gift Lounge.
The singer appears on the red carpet.
The Fifth Harmony singer walks the red carpet.
The Modern Family star sizzles in a red gown.
Peace, love and Jingle Ball. The Scandal star gets into a relaxing zone backstage with help from the co-founders of ENERGY Muse.
The singer walks the red carpet.
Best buds! The fellow Brits pose backstage at KIIS FM's Jingle Ball in the City of Angels.
The television personality checks Kris Kringle's naughty or nice list.
Two words: Too cute!
The pop star may be "Bad at Love" but she sure knows how to rock a photo opp.
The "Perfect" singer prepares for his headlining performance at KIIS FM's Jingle Ball show.