It was 53 years in the making.

A message in a bottle written by a 9-year-old girl in 1973 washed up on the Jersey Shore recently — while the man who discovered it found the late author’s sister just hours later and was shocked to learn that he and the girl share the same birthday.

Laurie Blair Brown, who was on vacation with her family in Ocean City in August 1973, wrote a playful note, which read:

“This bottle was adrift on August 20, 1973 on 2nd Street beach Ocean City as my captors were transporting me to an island off shore in the Atlantic. Please notify my family that a band of ruthless sponge fisherman are forcing me to dive for them in shark infested waters!”

The girl also wrote her Bernardsville home address in the dispatch, which she tucked inside the bottle.

Weeks ago, John Kauterman, co-founder of the nonprofit Tidelands Initiative, stumbled upon the long lost note by a marsh near the Garden State Parkway while on a cleanup in the wetlands of Upper Township — around 10 miles from where Blair Brown and her sisters tossed it.

“My first initial thought was like, ‘Okay, this sounds like a kid’s prank,’” Kauterman, 49, told NJ.com.

He then decided to post a photo of the message in a local Facebook group, which led to him learning that Blair Brown died in 2017 from cancer at the age of 52.

Within hours, Kauterman connected with Blair Brown’s sister, Allison Spencer, who revealed the letter actually contained her handwriting.

“I offered to write it for her because she wasn’t sure how to spell all of the words. It was her story, and I was the scribe,” Spencer told the outlet.

“My sister, who was a very creative and quirky person, had a really great sense of humor. She immediately latched onto this idea and she came up with the crazy story.”

Kauterman, who returned the letter to Spencer, was left awestruck that he was able to connect with her so quickly.

“I felt as though it’s kind of fascinating how the world works, where you can literally put something that’s been … essentially hiding for 53 years, put its content on the internet and be talking with the creator in like less than 12 hours,” he said, according to NJ.com.

Spencer, who also discovered that Kauterman serendipitously shares the same birthday as her late sister, told 6ABC she is planning to display her note in a shadow box in her home.

“She was really confident at the time we wrote it that it was going to be found,” she told the outlet.

“So I think she would say, ‘I told you so.’”