The 47-year-old star, who has Sunday, six, and three-year-old Faith, with singer husband Keith Urban, plays villain Millicent Clyde, a museum director who wants Paddington bear to be stuffed and mounted, reported the Daily Mirror.
"I was like, 'I'll do this for my children'. Then they're like, 'Oh my gosh, are you playing the bear's mummy?' I told them, 'I'm not playing the mummy, I'm playing...', and that's when I realised they can't go see this film.
"I'm vicious and awful in it. My daughter was mortified. They can't see it now," she said.