Celebrity Parents Reese Witherspoon and Ryan Phillippe Celebrate Son Deacon's 18th Birthday Together: 'Bursting with Pride' The coparents, who split in 2006, posed together with their son while celebrating his 18th birthday on Saturday By Tristan Balagtas Tristan Balagtas Digital News Writer, PEOPLE People Editorial Guidelines Published on October 23, 2021 08:56 PM Share Tweet Pin Email Photo: Ryan Phillippe/Instagram Deacon Phillippe is all grown up! Reese Witherspoon and Ryan Phillippe both shared touching Instagram tributes to their son in honor of his 18th birthday on Saturday. In a sweet post shared by the actor, 47, the coparents posed together with Deacon to celebrate the occasion. "Happy 18th birthday to our gorgeous, smart, talented, and caring son," Ryan 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)." Deacon reciprocated the love for his father, commenting, "Thanks dad!! I love you." Witherspoon added, "So proud of our boy ... I mean our ADULT Son! 😮❤️." Ryan Phillippe Soaks Up the Sun with Son Deacon in Photos from Their New Mexico Trip Meanwhile, the Legally Blonde star, 45, posted a series of snapshots of her musician son throughout the years, including one of him preparing to blow out the candles on his birthday cake. "How did this happen?!! @deaconphillippe is 18?!!" she captioned the photos. "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. 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 ✨ 🥺❤️🎂." Deacon also commented, "Love you mom!!" Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories. Reese Witherspoon's Kids Ava and Deacon Vacation with Their Significant Others: 'I'm So Lucky Man' The movie stars, who also share daughter Ava Phillippe, 22, were married for seven years before calling it quits in 2006. Witherspoon also shares son Tennessee James, 9, with husband Jim Toth, whom she wed in 2011. The Morning Show star recently opened up about watching her children get older in Interview's Summer 2021 cover story. "That makes me want to cry, the idea of having a long relationship with adult children," she told Tracee Ellis Ross in June. "I never expected the kind of relationship that I have with them, but it's so rewarding to be able to have kids that you can process life with a little bit, and they help me understand the complexities of what it means to be a human now," Witherspoon continued. "So I'm really, really grateful that these little humans are in my life." "Adult humans," she added. "I have two adult children now, Tracee. It's crazy."