Alongside a smattering of photos of James throughout the years, the Sex and the City star and proud mama wrote:
My beloved son, James Wilkie,
On this day, you are 18 years old.
I marvel at the passing of those years
but equally the young man you are becoming.
My love for you is an ache and an honor.
As you leap toward and into your future,
I remain your privileged and steadfast confident and joyful witness to the year ahead.
Happy birthday my first time voter.
I love you so.
Parker and Broderick, who tied the knot in 1997, have one of the longest-lasting marriages in Hollywood. Earlier this year, SJP posted a fantastic old-school photo of the pair in honor of their 23rd anniversary.
The couple has three children together—James, born in 2002, and twins Marion and Tabitha, born via surrogate in 2009.
Despite being such a high-profile couple, Parker and Broderick do their best to keep their family life private. But the Failure to Launch and Hocus Pocus star couldn’t resist posting some personal picks of her 18-year-old son, including one sweet shot of the two walking hand-in-hand across a gorgeous, grassy coastline.
One eagle-eyed commenter recognized the landscape as part of Donegal, a small town on the northwest coast of Ireland where the family has a second home. SJP replied that the scenic setting is "always making an appearance” in her family’s fond memories.
A number of stars wished SJP's first-born a happy birthday, including former Sex and the City co-star Willie Garson (“Happy Birthday JW, we love you, even as an adult!!”) and comedian and writer Amy Sedaris (“These are adorable pictures! HB James Wilkie you sure hit the jackpot with Sarah and Matthew!”). Bravo star and SJP BFF Andy Cohen also sent his regards, writing: “Cannot believe he is 18! He is an incredible young man.”