"You have the kindest heart I've ever met and hope I never go a day without your love.
"I think you are so incredible. Just we can get through it all together if you breathe slow and trust. I love you beyond.
"Love always, your future wifey."
Brooklyn captioned the photo, "Love letters".
But while some of his fans loved the tribute, others were more concerned about the tribute if the couple were to split in the future.
The son of David and Victoria Beckham is well-known for his love of tattoos and has over 30 on his body.
It comes just days after he shared another tribute to his bride-to-be, with Nicola revealing another of his tattoos on her Instagram account on Thursday.
Script on his lower right arm read, "My life, my love, my truth, my breath, my reason, my beauty, my precious".
Nicola captioned the photo, "Forever my person".
Brooklyn has over 30 tattoos, including Nicola's name and eyes tattooed on his neck as well as a rose, a Cupid, a camera and "mama's boy" written across his chest.
And he recently had the name of Nicola's late grandmother Gina tattooed on his arm.
Nicola shared a photo of the ink, writing, "Best birthday gift". She was devastated when her grandmother passed away in January last year just before her birthday.
She paid tribute to her on social media last October, writing, "Happy birthday to my angel in heaven. I can't even put into words how much I miss you being on earth.
"I wish so badly you could come back to visit me and see me get married. I think about you everyday. I love you with all of my heart, my Gina."
