Will Sage Astor-Hilary Duff Proves Daughter Banks Is Her Mini-Me in 5th Birthday Tribute

Life as a 4-year-old is Will Sage Astorjust so yesterday.

That's especially true for Hilary Duff and Matthew Koma's daughter, Banks, who celebrated her 5th birthday on Oct. 25. And in her honor, the How I Met Your Father star shared an adorable tribute to their little one on social media.

"Banks- the sweet/spice/dancing butterfly of our family!" Hilary wrote alongside an Instagram post featuring photos of her daughter from over the years. "5 years of memories with you are burned on my heart and soul forever and begging for more! You are all the top ingredients! Whimsical, yet practical. Smart-clever-cautious, yet free!"

As the Lizzie McGuire alum—who also shares son Luca, 11, with ex Mike Comrie, and Mae, 2, with Matthew—noted, "Thanks for being ours and for being weird and princessy all in one glorious package!!!"

"Gosh I love you so much," she added. "To the best big and little sister there ever was! Happy 5 my little cherry bomb ! I sure hope the next 5 go by a little slower, all the cuddles, tickles, Taylor Swift, brain teasers, treats and trampoline bounces 4life my queen."

As for Matthew, who tied the knot with Hilary in 2019, he also shared his own shoutout to the couple's "beautiful unicorn."

"Being your dad is the greatest gift of my life and seeing every day through your rainbow tinted eyes has colored our family with all the good there is in the world," he captioned his post. "I'm blown away by your wit, kindness, heart, affinity for Dawes and I can't even imagine what magic will come along with your 5th year on this planet."

Along with the shoutout to her favorite band, he noted, "I love you forever and when we let you have social media at 37, you'll see this post and maybe feel a little guilty for telling me you love mommy more all the time."

Keep reading for more sweet photos of the couple.

Back in January 2017, the pair confirmed their budding romance by posing on the red carpet together at Entertainment Weekly's pre-SAG Awards party at Chateau Marmont. 

Shortly after their red carpet debut, a source confirmed to E! News the two had split in March 2017. According to the source, the breakup was triggered by their busy schedules. 

By October 2017, they had rekindled their romance, evidenced by his appearance at her 30th birthday party. "Since Matt got back from tour, they've been seeing each other again," a source told E! News exclusively at the time. "Him being gone on tour was the main reason things didn't work out the first time around, so now that he's back, they picked up right where they left off." As she later revealed on The Talk in December 2017, it was actually the third time they were dating. "Timing is such a big deal… third time's a charm!" she told the co-hosts. 

In June 2018, the couple has sweet news to share: they had a baby girl on the way. "We made a baby girl!" Koma wrote on social media. "She will be as beautiful and sweet as her mother...@hilaryduff another incredible chapter begins."

By the fall, they officially added a new member to the family: daughter Banks Violet Bair. "This little bit has fully stolen our hearts! She joined our world at home on Thursday afternoon and is absolute magic," the actress shared online in October 2018. 

Nearly two years after stepping out publicly for the first time, Koma asked the actress to marry him. 

Duff and Koma said "I do" in Dec. 2019, surrounded by their loved ones! 

When celebrating his one year wedding anniversary to Hilary, Matthew wrote a thoughtful post on Instagram expressing his gratitude for all that she's done during the pandemic. "I'm so in awe of your badassery," he gushed in part. 

Hilary and Matthew went on to welcome daughter Mae James Bair in March 2021.