Hilary Duff is an "amazing" mother, says her sister.

The actress and her husband Mike Comrie welcomed their son Luca Cruz into the world at the end of March.

Hilary's elder sibling Haylie says the 24-year-old star has taken to motherhood with ease. "Amazing. She's doing so well. She's a great mom!" she exclaimed to E! Onine.

Haylie also gushed about her little nephew. The star says the family's new bundle of joy is the most wonderful addition.

"The baby's…beautiful. He's perfect," she smiled.

Hilary recently told of her "very easy" labour.

The blonde beauty discussed her relatively trouble-free delivery on The Ellen DeGeneres Show, where she also gushed about life as a new parent.

“Every single day, it seems like there’s a new face that they're making. He started to smile about a week ago, and that’s the coolest experience. It’s all good," she said.

“What is to come is such an amazing journey, and a lot of work. It’s just like the best thing that’s ever happened to you.”