Hilary Duff is in shock she's a mother.

The singer-and-actress welcomed her first child, son Luca Cruz, into the world on Tuesday (20.03.12) and admits she's completely in awe of him.

Hilary - who is married to former ice hockey player Mike Comrie - wrote on her twitter page: "He is the most wonderful, sweet, adorable baby.

"Wow, I can't believe I have a baby! Thank you for all the messages and well wishes. I love you all so much."

Hilary, 24, and Mike, 30, announced Luca's arrival yesterday (22.09.12) and said they were thrilled with the new addition to their family.

Hilary - who married Mike in 2010 - said: "Welcome to the World Luca Cruz Comrie! Tuesday evening, we became proud parents of a healthy 7 pound 6 ounce beautiful boy.

"We are overjoyed and feel like the luckiest parents in the world."

The former 'Lizzy McGuire' star was thrilled when she found out she was pregnant and admitted she couldn't wait to meet her son.

She said: "People keep saying to me, 'Sleep right now. Get your sleep!' I keep saying, 'I just want the baby here! I want to play and I'm ready to see what he looks like.'"