Singer-actress Hilary Duff says she likes to watch her two-year-old son Luca change on a weekly basis.

The 26-year-old had Luca with her estranged husband Mike Comrie and says the boy has changed her life, reports femalefirst.co.uk.

"There's no word good enough to describe how he's changed my life and how amazing he is. He's so much fun and it's amazing to watch him grow. Week by week he changes so much," she said.