On Saturday, JUSTIN BIEBER posted a picture of himself snuggling with SELENA GOMEZ, but then took it down.  Selena flew to Oslo for Justin's show Thursday, then reportedly followed him to Copenhagen for a gig on Saturday.  There's no official word that they're back together.

REESE WITHERSPOON and her husband Jim Toth were arrested early Friday morning in Atlanta.  He was popped for DUI, and she was cuffed for disorderly conduct during his arrest.  Police say she told them, quote, "Do you know my name? . . . You're about to find out who I am . . . You are going to be on national news."  She released a statement last night saying she was "deeply embarassed."