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Amanda Seyfried posts incredibly rare photo of baby son

The star gave birth to her son back in September

Matthew Moore

Amanda Seyfried is a doting mother to two adorable children, with her youngest being born back in September.

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The Mamma Mia! star is very protective of her brood and rarely shares photos of her children, and always hides their faces.

But the actress melted fans' hearts when she shared an adorable picture of her baby son, Thomas, playing with some of his toys.

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WATCH: Amanda Seyfried's husband adorably entertains their baby son

In the picture posted to her Instagram Stories, the tot was playing with a toy that counted up to five and needed a switch to be pulled for a different animal to pop up.

Amanda's four-year-old daughter, Nina, was helping her younger brother with the toy, keeping one of the doors open for him.

Speaking to Entertainment Tonight last year, the Hollywood star opened up about why she decided to keep her daughter's face away from the limelight.

"I don't share her face or anything [online]; I'll let her choose when she wants to do that later on in life," she explained.

The mother-of-two added: "But I can't help but share these insane conversations that [I'm] having with this this three-year-old. I mean, they're so in touch sometimes it's scary, but it's also super funny. I love it, and if I can share any of that, I will."

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Amanda's two children played together

When Amanda announced Thomas' arrival in September, she chose to do it in the best way possible, by raising awareness of two charities close to her heart – INARA and War Child.

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The Mean Girls star recently melted hearts after posting an adorable behind-the-scenes photo with her children for Mother's Day.

One image showed Nina in her dad, Thomas Sadoski's arms, while sweetly holding onto her mother's hand before she left for this year's Oscars.

Another image showed Amanda doting over her baby boy, who was sat in a pushchair, as she cooed over him before her big night, which saw her nominated for a Best Supporting Actress Oscar for her role in Mank.

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Amanda gave birth to Thomas in September

Captioning the images, Amanda wrote: "The best part is I'm a mom no matter what. And I get to share it all with my mom. All photos by @kwakualston."

Fans were quick to gush over the adorable family moments, with one commenting: "There aren't enough emojis in the world to express how much I love this. Happy Mother's Day!"

A second said: "These are just everything!" A third added: "Aww frame this! Just wow, what a mommy moment."

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