Jessica Simpson Shares Sweet Tribute on Daughter Maxwell's 8th Birthday: 'She Is a Gift'

Jessica Simpson and husband Eric Johnson have three children: Maxwell Drew, Ace Knute and Birdie Mae

Happy Birthday, Maxwell Drew!

Jessica Simpson’s oldest child, Maxwell, turned 8 on Friday, and the singer shared a touching tribute to her daughter in an Instagram post marking the occasion.

“Today my first born, Maxwell turned 8. She has more light in her soul than anyone I’ve ever known and shines far brighter than any star in the galaxies,” Simpson, 39, wrote. “She is a gift to everyone who knows her and deeply connects to those she has never met and prays for every night. Maxwell inspires me to be unapologetically myself in every way.”

The mom of three continued, “She has taught me that I don’t have to be perfect by continually reminding me I’m perfect for her. She is full of love, true compassion, mindful determination, intelligence, purposeful leadership, steadfast strength, deep wisdom, true beauty inside and out, hilarious sarcasm, feisty diplomatic reasoning, limitless talent, nonjudgmental awareness, relentless loyalty, and hope that manifests miracles.”

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Simpson, who said Maxwell is her “best friend,” also posted a video of her with her daughter hanging out and singing a duet of “This Little Light of Mine.”

In the video, Simpson comments on how well her daughter reads and Maxwell reveals that she’s on the second chapter of her mom’s new memoir, Open Book. Later, Maxwell teases Simpson after she makes a funny noise.

“Oh jeez, I don’t know what I’m gonna do with you,” Maxwell jokes, before the pair launch into another duet, singing “Amen” together.

Simpson shares Maxwell, as well as 1-year-old daughter Birdie Mae and son Ace Knute, 6½, with husband Eric Johnson.

Jessica Simpson with Maxwell Drew and Ace Knute. Kevin Mazur/Getty Images

The star recently opened up about how her children helped push her toward sobriety.

“Being a mother … my kids, at the time, were 5 and 4 … I was at a place where I was literally spiraling with the alcohol and I was missing out on moments with my children, and then they were seeing me and they were very confused,” Simpson told an audience member at The Kelly Clarkson Show, who asked what made her realize she finally “had to get sober.”

“I just wanted to be present and have clarity and be a good role model for my children,” Simpson continued. “ ‘Cause I always wanted to be a good role model for the world, so why in the world would I be stuck in this cycle of having to wake up and have a drink before going to one of their school assemblies?”

Speaking to PEOPLE in January, the Open Book author recalled how she hit “pretty rock bottom” while on the way to one of Maxwell’s school assemblies. “It was 7:30 in the morning and I’d already had a drink,” she said, later citing her sobriety as a "gift."

“There’s just no better gift,” she said. “There’s no better gift I can give my kids, there’s no better gift I can give my husband. More importantly, there’s no better gift I can give myself.”