Hilary Duff shows off baby bump in bikini snap during Hawaii vacation with son

Hilary Duff is taking it easy in paradise with her 6-year-old son, Luca, by her side.

“🌺 Max relax 🌺,” Duff wrote on Instagram Sunday, posting a photo of her growing baby bump while sporting a black two-piece bikini. The post garnered more than 353,000 likes as of Monday afternoon. 

The 30-year-old is expecting a baby girl with boyfriend Matthew Koma, 31.

Duff is in Hawaii for a mother-son vacation with a female friend accompanying them, E! reports. 

🌺 Max relax 🌺

A post shared by Hilary Duff (@hilaryduff) on

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The post comes just weeks after the actress described the difficulties of pregnancy, particularly the toll it has taken on her body.

“The boobs are big the belly is big the body is big. Man.. pregnancy is hard,” the "Younger" star said in a July 25 Instagram post. “Giving love to all mamas who make it look effortless... this journey is hard as hell and also incredibly special.”

She continued, “Lovely to have a little life inside and to day dream of all the new adventures to come buuuut almost impossible to get my own shoes on..sick of getting up 9 times a night to pee and looking at this weird body in the mirror that is not my own at the moment."

Duff said her baby bump is a reminder of how powerful women are.

“Women are so bad a--, this was just a note to remind myself and remind others how’s strong and beautiful you are! WE GOT THIS!” she said.

HILARY DUFF SAYS BEING PREGNANT IS ‘HARD AS HELL AND ALSO INCREDIBLY SPECIAL’ IN INSTAGRAM POST

Duff revealed her pregnancy — and the baby's gender — to fans earlier this summer.

“Guess what guys! @matthewkoma and I made a little princess of our own and we couldn’t be more excited!!!!!!” she wrote in a June 8 Instagram post.

Koma later shared the same snap and captioned it, "We made a baby girl! She will be as beautiful and sweet as her mother... @hilaryduff another incredible chapter begins."

Duff and the singer have dated on-and-off for a few years, most recently getting back together in October.

She and ex-husband Mike Comrie are parents to son Luca.

Fox News’ Sasha Savitsky contributed to this report.