Actress Hilary Duff says the last five years of her life -- since her son Luca Cruz Comrie was born -- have been "the best and the hardest".
The 29-year-old took to Instagram to post a heartfelt message in celebration of his birthday on Monday, reports eonline.com.
While sharing a photograph of her son on the photo-sharing platform, Duff wrote: "Hey kid... The past five years have been the best, hardest, most blessed years of my life. I love you so much. The world is yours my love... I hope you take it Happy Birthday Luca Cruz."
Luca is Duff's only child with her former husband Mike Comrie.