"He is truly our silver lining from the past crazy year and we couldn't be more grateful," Eva Amurri said

Happy birthday, Mateo Antoni!

On Saturday, Eva Amurri marked her son's first birthday with a sweet video montage of adorable clips of the youngest member of her family from over the past year.

"Our little butterball of love is ONE!," Amurri wrote alongside the post, which was set to the tune of an Ellie Goulding song. "It has gone by in a flash 😭."

"He is truly our silver lining from the past crazy year and we couldn't be more grateful ❤️," she continued, adding the hashtags, "#HappilyEvaAfter" "#MateoAntoni" and "#Firstbirthday."

Amurri is also mom to daughter Marlowe Mae, 6, and son Major James, 4, with her ex Kyle Martino.

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Last March, Amurri announced the arrival of her third child in a newsletter for her lifestyle website, Happily Eva After.

"Kyle, Marlowe, Major, and I are thrilled to announce the birth of our littlest love: Mateo Antoni Martino," Amurri wrote in the newsletter at the time. "He arrived safely & sweetly at home, March 13th at 3:58pm, weighing 7 lbs 11 oz and 21 inches long."

"Our hearts are so full!" she added. "Thank you for the well wishes, and I look forward to sharing more soon!"

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Amurri and Martino previously announced her pregnancy in September 2019, about two months before revealing they had split after eight years of marriage. "We are committed to, and excited about, raising our three beautiful children as close friends and deep partners, and we have the utmost respect for one another," they wrote in identical Instagram posts at the time.

Amurri — who is the daughter of actress Susan Sarandon — previously confirmed to PEOPLE that she and Martino were legally single when they welcomed Mateo in March 2020, revealing that they had finalized their divorce a month and a half earlier.

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Both Martino and Amurri have been candid about their dedication to their children as they navigate the world of co-parenting amid the ongoing COVID-19 pandemic.

Martino was previously staying in Amurri's studio on her Westport, Connecticut, property so they could social distance together as a family.

"It was either he isolates on his own and doesn't see the kids for who knows how long or we isolate together. It was an obvious choice for the kids' sake and his sake," Amurri told Otherland co-founder and CEO Abigail Cook Stone in April 2020. "It's been great, surprisingly. It's obviously had its moments."

As for the former couple's "amicable" divorce, the actress said that she and Martino mediated it on their own, adding, "We've just been building off of that and it's working thus far."