Hilary Duff flats luca sunglasses baby

We can't believe how fast Hilary Duff's little boy is growing up!

Hilary carried her adorable son Luca out of a Mommy and Me class in the valley on Wednesday, and not only is he no longer a baby, but she's looking super svelte these days!

When she's not on parent duty or shopping, she's slowly getting back into acting. We already knew she was guest-starring on Two And A Half Men, but we totally forgot her episode aired today! Last night Hil tweeted, "Guess what?! I'm gonna be on the season finale of #TwoAndAHalfMen tomm! Thursday @ 8:31pm ET/PT on CBS! Don't be a minute late ;)." Can't wait to check it out!