"Welcome to the World Luca Cruz Comrie!" she tweeted. "Tuesday evening, we became proud parents of a healthy 7 pound 6 ounce beautiful boy."
She followed it up by tweeting, "We are overjoyed and feel like the luckiest parents in the world. He is surrounded by so much love!! Mom and baby are both doing extremely well."
Duff and Comrie, who recently retired from the NHL, revealed they were expecting their first child back in August, one year after their wedding anniversary. They announced the news on Duff's website, writing, "We are extremely happy and are ready to start this new chapter in our lives."
In October, Duff — who was more than four months pregnant at the time — sat down with MTV News and told us she had a feeling that she was expecting a baby boy.
"Everyone else says it's a girl, but I think it's a boy," Duff said. "I'd be happy with a girl, but my sister's like, 'You can't keep saying that, because then when it's a girl, everyone's gonna be like, "You really wanted a boy!" ' I don't care what I get, but every time I think about it or dream about it, I see a boy."
At the time, Duff was in the process of making a very tough decision: picking a baby name.
"If we give the baby kind of a unique name, we need to give it a normal middle name in case it hates it and wants to, like, fit in better, and then maybe we just need to go totally traditional," Duff said. "And we're like, 'How can we be naming it before we even see it?' There's so much to think about!"
The former "Lizzie McGuire" star got lucky during her first pregnancy, saying that other than the lack of sleep, it's been a relatively calm experience.
"I feel really good. It's been pretty easy, and I haven't gotten sick at all, and I don't have too many cravings," Duff told MTV News. "It's so different. It's literally like an alien has taken over your body. One day I'll have a good day, and one day I'll have a bad day, and it kinda goes like that."
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