When the song was over, Ariana said, "Happy birthday, Saffie," before looking up and blowing a kiss.After the show, the singer alsoInstagrammed Justin Bieber’s Newest Modeling Gig Is All Kinds Of EpicSo, Justin Bieber Went to Prom This WeekendContentView Iframe URL ’s mom Patti Mallette is well known to fans. She’s a mainstay on Justin’s tours and has made appearances in his concert moviesNever Say NeverandBelieve Justin Bieber and Cara Delevingne Just Broke the Only Rule of the Met Gala