Ariana Grande & Austin Mahone: Z100's Jingle Ball Performers!

Ariana Grande is dazzling white while posing backstage at Z100′s Jingle Ball 2013 held at Madison Square Garden on Friday (December 13) in New York City.

Before taking the stage, the 20-year-old singer was introduced by Anna Kendrick.

PHOTOS: Check out the latest pics of Ariana Grande

Ariana was joined at the concert by Austin Mahone and Fifth Harmony.

“Just performed at Madison Square Garden.. pretended I was in my grandparents living room. Literally can’t believe that just happened!” Ariana tweeted after her performance.

20+ pictures inside of Ariana Grande and Austin Mahone attending Z100′s Jingle Ball 2013…