The pretty actress claims she was unpopular with boys during her teen years because she lacked the curves they desired, and her date, a member of the school's American football team, didn't even want to dance with her at the big end-of-year event.
Rivera, who is dating rapper Big Sean, admits she was heartbroken by the snub, but now she's a Tv star, she is eager to rub her success into the unnamed suitor's face.
She tells Complex magazine, "He started talking about how skinny I was. All of his friends were like, 'You need a thick (big) girl.' He was grinding on every other girl at the dance while I sat alone at the table, looking like a senorita. I didn't even dance. It was horrible.
"Then he said, 'So, are you coming to the hotel?' And I was like, 'No, my dad is picking me up. On top of that (his bad behaviour at the prom), you're trying to have sex with me? How rude are you?'
"Best believe I'll be at that reunion though."