The Hollywood couple celebrated their eldest son Dylan Douglas's 26th birthday on August 8, sharing heartfelt tributes alongside a collection of never-before-seen family photographs that captured his journey from childhood to adulthood. © Instagram Catherine with Dylan"Happy birthday to my son Dylan!!!!!" © Instagram Dylan all grown upMichael's words of wisdomMichael, 81, also paid tribute with a recent father-and-son photograph taken during one of their adventures together. © Instagram Carys with DylanThe pair have long shared a close relationship, often travelling together and enjoying the family's beloved retreat in Mallorca. The photos showed the pair trekking through spectacular mountain scenery with backpacks and hiking poles, highlighting their shared love of adventure.