Reese Witherspoon and Ryan Phillippe praise son Deacon in touching birthday tributes

Reese Witherspoon and Ryan Phillippe both shared touching tributes to their son Deacon Phillippe on his birthday, and it sure is a big one! The second child of the famous couple turned 18 years old on Saturday!

To mark the special milestone, the elder Philippe shared a photo with his son and ex-wife paired with a touching caption honoring their modern family.

"Happy 18th birthday to our gorgeous, smart, talented, and caring son," the 47-year-old actor wrote. "You are a true light in this world and are so loved by all who know you. We are lucky to be your mom and dad. Love you, pup.. (I’d say we did pretty good @reesewitherspoon)."

In 1997, Witherspoon and Phillippe met just before filming the teen drama "Cruel Intentions." They wed in June 1999 and a few months later had their first child, Ava Elizabeth. Four years later, the couple welcomed Deacon into the world. In 2006, the couple announced their separation after seven years of marriage.

Witherspoon, 45, also celebrated her son's big day with an Instagram post as well, sharing a gallery of images showing Deacon growing up throughout the years.

"How did this happen?!!" the "Legally Blonde" star emphatically asked. "@deaconphillippe is 18?!!"

"One day he was trading Pokémon cards, singing Bruno Mars songs, and playing 'American Ninja Warrior' in the backyard. The next day, he is taller than me, cooking the family steaks on the grill and making his own music with his best friends," she said. "My heart is bursting with pride about the young man he is becoming. Happy 18th Birthday Deacon! I love you to the moon around the sun and all the stars."

Phillippe and Witherspoon have been open about the importance of amicable co-parenting over the years.

"You have to get to that point as a divorced parent, as any parent, where you’re not putting yourself first," he said in 2016. "You want the kids' experience to be its own and not like, 'Well, I need to have my time!' We have been very good about that."