September 2nd will always be a “bittersweet day” for Mark Wahlberg. The 50-year-old actor took to Instagram on Thursday to wish his daughter Ella Rae Wahlberg a happy 18th birthday, sharing a throwback photo of Ella as a baby. In that same post, Mark also shared a throwback shot of his late sister Debbie Wahlberg, who died after suffering a heart attack and septic shock from a kidney infection on Sept. 2, 2003, the same day that Ella was born.