Hilary Duff has become a mum for the first time after giving birth to a baby boy.

The US actress and singer announced that she and her husband Mike Comrie welcomed son Luca Cruz Comrie on Tuesday night.

Their new addition weighed in at 7 pounds, 6 ounces.

Hilary tweeted her fans to tell them her joyous news: "Welcome to the World Luca Cruz Comrie! Tuesday evening, we became proud parents of a healthy 7 pound 6 ounce beautiful boy."

She later told fans of her and Mike's happiness: "We are overjoyed and feel like the luckiest parents in the world."

The 24-year-old gained fame as the star of Disney's Lizzie McGuire and more recently had a recurring role on hit TV series Gossip Girl.

Photo: © Rex