The couple shared separate posts on Wednesday morning, with David posting a picture of Brooklyn as a child, in which he’s seen sporting a temporary tattoo (as an adult, the eldest Beckham has now followed in his dad’s footsteps and boasts an array of body art).
“Happy 21st to my big boy,” David wrote. “What more can I say about you other than you have grown into the most beautiful human being and that makes dad so proud.
“You are kind, passionate and caring and as a father that’s what you want to see in your son... we have had so many great moments as a father and son together like lifting trophies in all the places that I won them and for me that was always my dream.”
David added: “I love you bust have the most amazing day because u deserve it.”
Victoria later shared a photo of David holding Brooklyn as a baby, writing: “21 years ago today the most beautiful soul came into the world and changed our lives forever.
“Sensitive, sweet, kind and funny, you are our everything. I love you so much.”
Brooklyn also commented on his mum’s post, saying simply: “I love you so much.”
The Beckhams’ younger sons, Romeo and Cruz, also posted tributes to their older brother on his 21st birthday.
It’s been a big 12 months for the Beckhams when it comes to big family celebrations, with David and Victoria marking their 20th wedding anniversary in 2019.
Shortly after this, they also shared photos from their daughter Harper’s star-studded christening.