The 37-year-old actress revealed earlier this week she had undergone a double mastectomy after tests revealed she carried the BRCA1 gene and had an 87 per cent chance of contracting breast cancer and a 50 per cent chance of contracting ovarian cancer, which killed her mother, Marcheline Bertrand.
And Haven thinks her decision to go public will be helpful to others, reported E! online.
"There is no question Angelina makes a difference in our world by bringing awareness to so many causes. Her compassion for humanity alone always makes me honoured to call her my sister," he said.
The actor, who married Jolie in May 2000 and separated from in June 2002, said, "We've communicated but not talked. I think she is not only a tribute to mankind, but she's done so much for people, she deserves absolutely the best in every way. She always has and always will in my book.