"I love it. I knew for a while that she was going to adopt," Thornton tells People magazine in its Aug. 8 issue. "She cares so much for kids who don't have anything."
"Any kid Angelina adopts is going to have a great mother," adds Thornton, who stars in the new movie "Bad News Bears."
Before their split in 2002, Jolie and Thornton adopted a baby boy, Maddox, from Cambodia. Jolie is often seen carrying Maddox in her arms.
Thornton says he doesn't get to see Jolie and Maddox much.
"She's all over the world and I live in California," he says. "I see them every time she comes to town, but that hasn't been very often in the last couple of years."
Brad Pitt, Jolie's "Mr. & Mrs. Smith" co-star, accompanied the actress when she picked up her daughter.
"Nothing surprises me," Thornton said.