George Clooney mourns death of loved one: ‘I will miss her terribly’

George Clooney is mourning the loss of his sister, Adelia “Ada” Zeidler, who died on Friday, December 19, at the age of 65 following a battle with cancer.

Speaking to PEOPLE, the 64-year-old actor described his sister as his “hero” and praised her courage in facing the illness.

“My sister, Ada, was my hero. She faced down cancer with courage and humor. I’ve never met anyone so brave. Amal and I will miss her terribly,” he said in the statement.

According to her obituary, she died “peacefully” while “surrounded by the people she loved” at St Elizabeth healthcare in Edgewood, Kentucky.

“In addition to her parents, she leaves behind her beloved children, Nick Zeidler and Allison Zeidler Herolaga and her husband, Kenny; her brother, George Clooney and his wife, Amal; and several uncles, aunts, and cousins,” the obituary concluded.

Ada – who was named after her great-grandmother – was born in Los Angeles on May 2, 1960, to journalist and TV host Nick Clooney and writer Nina Bruce Warren.

George Clooney shared a special bond with her and even read scripture during her wedding to Norman Zeidler, a retired army captain, in Augusta in 1987.

While she led a very private life, she supported her brother publicly over the years, including attending his wedding to wife Amal in Venice in 2014.