“She will be an amazing mom,” Butler told PEOPLE at the premiere of his new film Law Abiding Citizen in New York City Wednesday. “She’s incredibly responsible, smart and loving. This is a huge deal for her and she’s going to take to it like a duck to water.”
PHOTOS: Katherine Introduces Baby Naleigh
In fact, the Scottish actor, 39, said Heigl used her maternal instincts on him while working together. “She mothered me,” he said. “Anytime I was feeling under the weather or was having a hard day, that’s when she was amazing. She would always come and check on me. I think she’s naturally a caretaker in the best way.”
Heigl, 30, and her musician husband Josh Kelley, 29, recently adopted 10-month old Naleigh from South Korea after a six-month long process.
“It’s great that she did that,” Butler said of Heigl’s decision to adopt a special needs baby. “It’s just a testament to her character and to her personality that she went out of her way to do that. It’s a beautiful thing.”