A tipster contacted the National Center for Missing and Exploited Children (NCMEC) earlier this week to report the potential sighting of a woman who may have gone missing as a baby 51 years ago.

The reported sighting occurred in Charleston, South Carolina, according to the organization dedicated to finding missing children.

"Receiving tips for cases that are decades old is a rare occurrence, but it’s not unheard of," John Bischoff, head of NCMEC's Missing Children Division, told Fox News Digital. "At NCMEC, we will never forget about a missing child, and we are happy to see much of the community has not forgotten about Melissa either."

Melissa Highsmith disappeared from Fort Worth, Texas, Aug. 23, 1971, when she was just 21 months old, according to NCMEC.

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Bischoff said the fact that the tipster looked at NCMEC's photos of Highland and recognized and reported a potential sighting "is outstanding."

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Highsmith's mother, a recently separated mother who had just moved to Fort Worth and was working as a waitress at the time, had placed an advertisement in the local newspaper for a babysitter to watch over her daughter. A woman responded to the ad and agreed to meet Highsmith's mother at the restaurant where she worked, but the respondent never showed up.

Later on, the prospective babysitter called Highsmith's mother and expressed her interest in the job, saying she had a big yard and cared for other children. Highsmith's mother hired the babysitter, according to NCMEC.

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The babysitter picked up the 21-month-old toddler while she was in the care of her mother's roommate and her mother was at work. Her mother's roommate said the woman who picked Highsmith up at the time seemed "nice" and "dressed to impress, wearing white gloves," NCMEC said in a Thursday tweet.

Highsmith hadn't been seen since her mother called law enforcement the day she disappeared in 1971.

"All it takes is one person to see the right thing and do something about it," Bischoff said. "We are unsure if this tip will go anywhere, but it’s clear the public has not forgotten about Melissa. Law enforcement hasn’t and neither have we."

NCMEC is asking anyone with information to contact 1-800-THE-LOST (1-800-843-5678).