Gerard Butler: Katherine Heigl Will Take To Motherhood “Like A Duck To Water”

Katherine Heigl’s Ugly Truth costar Gerard Butler has nothing but praise for her in her new role as a mother.

“She will be an amazing mom,” Gerard tells PEOPLE at the Law Abiding Citizen premiere in New York on Wednesday (September 23). “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.”

He goes on to say that, on the set, Katherine honed her maternal instincts with him: “She mothered me,” says the 39-year-old Scottish actor. “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.”

Katherine, 30, and husband Josh Kelley, 29, recently adopted 10-month-old Naleigh from South Korea. A process which took only six months.

“It’s great that she did that,” says Gerard about Katherine and Josh’s decision to adopt a baby with special needs. “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.”