Hilary Duff Thinks Her Son Is 'Cute When He's Mad'

06/14/2012 at 11:15 AM EDT

What's with the look on little Luca's face as his mom Hilary Duff holds him?

His grandfather thinks he has an idea.

"I sent my dad this pic and he said 'luca told me to tell u, u made his oatmeal lumpy' lol," the actress, 24, Tweeted. "He is cute when he's mad!"

And her adorable son (even when he's crying) keeps the new mom happily occupied.

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"I should be sleeping but instead I am watching luca break out of his swaddle on the video monitor," she Tweeted on Wednesday night. "So funny...little guy is not giving up."

Born on March 20, Luca Cruz Comrie is still cute enough to keep his mom and dad, hockey player Mike Comrie, smiling. And the family has been enjoying plenty of quality time together.

Duff recently Tweeted, "Perfect Sunday on the couch with Luca and Mikey! Watched hang over 2 annnnnd couples retreat. Sooo funny I'm ready for bed lol."

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