Tori Spelling Reflects on Motherhood in Tribute to Son Beau as He Turns 6: 'You Complete All of Us'

Tori Spelling/Instagram Tori Spelling and son Beau

Tori Spelling's youngest baby is growing up.

On Thursday, the family celebrated as son Beau — the youngest of the Love at First Lie host's five children with husband Dean McDermott — turned 6 years old.

Sharing an Instagram Reel that highlights moments in Spelling's pregnancy with Beau and the earlier days of his life, Spelling wrote, "Can't believe my baby is 6 today."

"Beau is the light and soul of our entire family. He brings such joy and laughs into my life, his dad's life, and all of his siblings," she continued. "Finality is a hard thing for me. Knowing Beau was the last was tough because I love the journey of pregnancy so much. And, every second of motherhood."

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She continued, "But knowing Beau in the physical sense for 6 years now, it all makes perfect sense. He completes all of us."

Calling her little boy "so special. So kind. So smart. And, so darn funny!" she continued, "We celebrate you every day Beau Beau Bear! I love you with all my heart. I always thank all of my babies for choosing me to guide and love them thru this lifetime. I thank you, Beau, for this final gift of motherhood. We are a good pair. My cuddler. My love! I love you forever, Beau Dean. xoxo."

Beau also got a birthday shoutout from big sister Stella, 14, who shared a silly photo of the pair with sister Hattie, 11.

Tori Spelling/Instagram Tori Spelling and Dean McDermott's son Beau and daughters Hattie and Stella

"Happy birthday to my little partner in crime," the teen wrote. "I love you so so much Beau Beau bear!!💗"

In addition to Beau, Hattie, and Stella, Spelling, 49, is also mom to sons Finn, 10, and Liam, 15.

Last September, Spelling opened up about how raising her kids at their different ages and stages comes with its own challenges, but she's excited to see how they're "evolving every day."

"They're constantly changing, they're learning. They're not stagnant and I feel like as adults sometimes we get to that place," Spelling told PEOPLE.

"I'm there for them a hundred percent but I'm learning from them too which is a really cool experience that I don't think you ever really know is gonna happen before you have kids."