On Wednesday, the 42-year-old "Predator" actress took to Instagram to share a candid video of herself in a blue bikini and tortoise shell sunglasses, sitting along the shore of a beach with her nearly one-year-old son, Malcolm, whom she shares with comedian John Mulaney.
In the clip, Malcolm picks up a seashell from the ground and attempts to put it in his mouth before Munn stops him just in time.
"We've entered the 'puts everything in their mouth' era," she quipped in the caption for her more than 2.7 million followers.
Munn's video was quickly met with comments from fans praising her beauty and transparency around early motherhood.
"You look amazing! And this is too cute!" one fan shared, while another added, "Hot mama! You look amazing. And this is such a cute but frustrating phase haha. You got this!"
"Classic motherhood struggles lol. You look fabulous though!" someone else wrote.
"You look fantastic. Being a mom looks great on you!" another fan penned.
"I like to call it the 'tasting your textures' era," one person suggested.
"Officially the hottest mom on the 'Gram," one person commented, alongside a flame emoji.
The actress shared another "hilarious and adorable" video of her son last month after celebrating his first Halloween dressed up as Munn's mother, Kim Munn.
In the Instagram Reel, Malcolm sat on a sofa next to a box of Wheat Thins crackers and a container of sunflower seeds while holding a long pepperoni stick. He also wore blue flip-flops, red floral pants, a grey T-shirt and a black bob-cut wig.
"Happy Halloween," the on-screen text reads. "He hated this wig."
"Malcolm dressed up as the most iconic figure in his life... my mom," she captioned the post.
The "X-Men: Apocalypse" star also shared a photo of her mother in an Instagram Story for reference, where Kim wore a similar hairstyle and outfit while sitting on a chair with a box of crackers, a bag of sunflower seeds and a pepperoni stick.
"Identical," Olivia wrote over the photo.