Weatherly was a singer-songwriter in his own right, notably working in the pop and country genres, but was also known for the songs he penned for other artists, including "Midnight Train to Georgia" for Glady Knight & The Pips.
The soul legend, 76, tweeted about her late friend on Thursday.
"I’m missing Jim Weatherly already. He was about life and love," she said. "Neither One of Us and Midnight Train - I remember him getting his Grammys for those. We were just made for each other. We grew our lives together. I’m gonna miss him terribly and love him always."
He also penned the song "Neither One of Us (Wants to Be the First to Say Goodbye)" for the group.
Weatherly's death was also confirmed to the Tennessean by music mogul Charlie Monk.
The star died Wednesday at his home and the family has attributed the death to natural causes, the outlet reports.
Contrary to Knight's tweet, Weatherly never won a Grammy and was not nominated for "Neither One of Us," but according to the Grammy's official website, he was nominated in 1973 for best rhythm & blues song, "Midnight Train to Georgia."
People magazine reports that the song was originally written as "Midnight Plane to Houston," but was changed by Knight, commonly known as the Empress of Soul.
In the same year, Knight and her Pips won a Grammy for their vocal performance on the track, as well as for "Neither One of Us."
In 2006, Weatherly was inducted into the Nashville Songwriters Hall of Fame. He had a top 10 country hit with "I'll Still Love You" in 1975, according to the Nashville Songwriters Foundation.
Fox News has reached out to Monk for comment.