Hilary Duff and Luca hit the beach during Mexican getaway

Suzy Byrne
Omg Goddess

Hilary Duff has been using Twitter to share her son Luca Cruz's major milestones, including his first Mexican vacation!

Duff, 24, posted a photo of herself with the 3-month-old tyke on the beach in Mexico. The photo, featuring a very scenic backdrop, shows the first-time mom cradling her infant son, who is outfitted in a yellow, white, and gray hooded beach cover up. The actress captioned it, rather simply, "Paradise…"

The former "Lizzie McGuire" star, who is married to retired NHL player Mike Comrie, is enjoying a getaway with her sister, Haylie Duff, and their mother. "Ahh, all tucked in," she tweeted Thursday night before going to sleep. "Baby down. Such a great trip with my favorite people."

Earlier this week, Duff, who has been hitting the gym hard since the birth of her son, was photographed looking ab fab in a bikini while holding Luca at her hotel pool. (Check out the omg! NOW video below for the photo and story.)  In addition to yoga, Pilates, and spinning, she has been working out with celebrity trainer Harley Pasternak and getting gourmet meal delivered by Freshology to slim down.

"There is a little bit of pressure" to lose baby weight, she told Parade in April. However, she acknowledged that "most of it comes from me."

Duff has been sharing lots of photos of her first born with her Twitter followers. Last week she snapped Luca in his crib looking upset and wrote, "What does this little turkey have to frown about?" She also posted several of the professional pictures she had taken during a family photo shoot.

As for plans to make the family of three a family of four, Duff told Parade she didn't want to wait too long. "Right now, I'm focused on being the best mom I can be and when I start working again, I'll see how I juggle everything. But then again, my sister and I are very close so I want Luca to have someone close [to his age] -- but not too close!"

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