In the Lachey family, Christmas Eve is a special day for more than one reason.

In a new post, shared to Vanessa Lachey’s Instagram account, the mom of three opens up about the day her youngest child, son Phoenix Robert, came into the world six years ago under a tumultuous series of events.

“It was 2:34 am on December 24th, 2016. I had been in the hospital for 10 days already because my water broke 11 weeks early and we were trying to do all we could to keep him healthy and in my womb for a few more weeks,” Lachey, 42, recalled in the caption of a photo of Phoenix dressed in Christmas pyjamas while smiling next to a gingerbread house.

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“Well, he had different plans. I went to the restroom, and when I stood up I realized my umbilical cord was coming out an umbilical cord prolapse. Immediately I was taken to an emergency delivery,” she continued. “6 years later, you’d never know he was a premie!”

The “NCIS: Hawaii” star noted that whenever she tells her little one about his birth story, “he says, ‘Mama, I came early because I didn’t want to miss Christmas!’.”

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“So, every year, we do all the things, and it warms my heart (his too!) One of our favourite family traditions is a gingerbread house we have every year,” Lachey shared in the sweet post. “The night of his birthday he’s allowed to eat it! (Here he’s deciding where he will start!) Haha! Fun memories.”

“Happiest Birthday to my Phoenix! The missing piece to our family puzzle we never knew we needed!,” the actress concluded.

Vanessa and her husband Nick Lachey are also parents to daughter Brooklyn Elisabeth, 7, and son Camden John, 9.