Washington, June 14 -- Brad Pitt and Angelina Jolie's son Knox has dropped "Pitt" from his last name on his high school diploma, weeks before turning 18, marking the latest development in the family's ongoing post-divorce dynamics.

Brad Pitt and Angelina Jolie's son Knox Jolie-Pitt has reportedly used "Knox Jolie" instead of his full legal surname on his high school graduation certificate, according to Page Six.

According to what a source told Page Six, the teenager, who turns 18 on July 12, graduated earlier this month from Fusion Academy in Los Angeles and opted to drop "Pitt" from his last name on his diploma.

Knox marked his graduation ceremony alongside his mother, Angelina Jolie, his elder brother Pax Jolie-Pitt (22), elder siste...