Leah Pickett posted the photo on her Twitter Sunday, which shows the Dallas Buyers Club star posing with her aunt at the pair's high school prom.
McConaughey won Best Actor at Sunday night's Oscar ceremony for his role as real-life AIDS patient Ron Woodruff in Dallas Buyers Club. In his acceptance speech, the actor said he needs three things in his life each day: God, family, and someone to look up to as a hero. He ended his speech with his signature line from Dazed and Confused, "All right, all right, all right," to audience laughter and applause.
Notable deaths of 2014 [PHOTOS]