The Good Will Hunting star, who broke-up with the star in 2004 after a two-year relationship, said that they "touch base" and that he is happy for her success.
"We don't have the kind of relationship where she relies on me for advice, but we do have the kind of relationship where there'll be an e-mail saying, 'Oh, your movie looks great'," he told The Hollywood Reporter.
The 40-year-old added: "I remember when she got American Idol. I said: 'This was really smart. Good luck.' I touch base. I respect her. I like her. She's put up with some stuff that was unfair in her life, and I'm really pleased to see her successful."
"It gave me a stronger sense of feeling protective about my family. There's a lot of crazy, weird people out there. It's an ugly world," he said.
The actor - who will be at the BFI London Film Festival for political thriller Argo, which he stars in and directed - said he used to be a Hollywood wild child.
"I went to rehab for being 29 and partying too much and not having a lot of boundaries," he added.