Hilary Duff loves watching her 'kind' boy growing up

Hilary Duff recently opened up about the growing up phase of her four-year-old 'kind boy' Luca.

In a recent interview, the 28-year-old actress, who shares custody of Luca with her former husband Mike Comrie, expressed delight watching her son growing up, and said, "Every age has always obviously been great. It does get better and better. Four's a little tough, not gonna lie," E! Online reports.

Adding on to this, the 'Lizzie McGuire' star said, "There's been a few challenges but he's, I guess how well he communicates and how funny he is and getting to see his imagination just kind of go wild, like when he's playing with his toys and I am cooking dinner or I'm hanging back and not necessarily like, all up in his business, to hear the stories he comes up with with his toys, it's so imaginative."

Duff, who welcomed her little bundle of joy on March 20, 2012, further said that her little sweet boy makes feel her very proud and she is lucky to have him in her life.