Many celebrities have paid tribute and remembered Willie Garson over the past few months after his death. More recently, his only child pens an emotional letter online on what would have been his father's 58th birthday.

According to Daily Mail UK, the 21-year-old child of the actor took to his Instagram account to share an emotional tribute.

Nathen Garson posted two throwback snaps of him and his father. He captioned the post, "Happy birthday papa. Miss you tons and love you."

A post shared by instagram

Per the outlet, the "Sex and the City" actor adopted Nathen when he was seven years old in 2009.

In a previous interview with Page Six, Willie revealed he always wanted to have a child, so he decided to adopt one despite being a single parent.

He also revealed that he had a relationship with a woman for over 20 years, but "she never wanted to have a child."

At the time, he was going through a mid-life crisis, and he wanted to be a father.

In a separate interview with Authority Magazine, Willie gave fans a glimpse into his fatherhood, saying he was a "narcissist actor" and his life changed as he is bound to take care of someone else.

He was in his mid-40s when he adopted his son, which instantly changed him. He mentioned giving "someone a childhood who did not really have a real one."

The actor resonated with his fatherhood as he also gained one because his parents were "not child friendly."

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Today, Nathen Garson is now 21 years old and is currently a student at the College of Wooster studying psychology minor in mathematics. He's completing his sophomore year while playing tennis for the university.

At the time of the actor's death, Nathen shared an emotional tribute to his dad, writing, "I'm so glad you got to share all your adventures with me and were able to accomplish so much. I'm so proud of you."

Willie Garson's passing shocked "Sex and the City" fans. The 57-year-old actor died on September 21 after a short illness.

The actor was filming the highly-anticipated "SATC" series titled "And Just Like That" at the time. He had pancreatic cancer.

It was previously reported that the actor only shared his cancer diagnosis to a few of his good friends from the show, like Sarah Jessica Parker and Mario Cantone.

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