The 'I Knew You Were Trouble' singer said in an interview that she'd seen one of her friends take back a cheat, and it's thought she was talking about teen tearaway Bieber and Selena.
Taylor told Glamour magazine: "I've seen my friends take someone back after they've cheated because they fit perfectly".
Her friend Selena kissed her ex backstage and Swift was having none of it.
"You do not want to open that can of worms," Taylor reportedly said when asked what she and Selena were gossiping about at the time he picked up his award.
Re-live that tongue moment below.