Wanda Young, a founding member of the 1960s Motown girl group The Marvelettes has passed away at the age of 78, Rolling Stone reports.

While the specifics surrounding her death are still forthcoming, music fans mourned the loss of the "I’ll Keep Holding On" singer.

"We are so saddened by the news of Wanda Young of the Marvelettes passing," the official Classic Motown account tweeted on December 16. "What an impact she has had on the world of Classic Motown and the lives of so many. Her legacy will continue to live on."

Born just outside of Detroit in Inkster, Michigan on August 9, 1943, Young joined The Marvelettes in 1961 and sung the lead on many of the groups songs, including "Don’t Mess With Bill,” “My Baby Must Be a Magician,” and “The Hunter Gets Captured by the Game.” The group's most notable hit, "Please Mr. Postman," topped the Billboard charts in December 1961, becoming Motown's first number one hit and establishing the label as a soul music powerhouse.

In the 2004 book The Original Marvelettes: Motown's Mystery Girl Group, group member Katherine Anderson recalled the song's impact. “We were all surprised when ‘Postman’ hit so big,” she said. “The most surprised was Motown.”

“Motown became even more known once we hit with Please Mr. Postman.’ In my opinion, where Motown wanted to go. The Marvelettes came in and kicked the door open," Anderson said.

Young was married to Bobby Rogers of The Miracles for 12 years and left the group in the late '60s to focus on her budding family. The group briefly reunited in 1990 for the album, The Marvelettes…Now! and were inducted into the Rhythm & Blues Foundation’s Hall of Fame in 1995 and the Vocal Group Hall of Fame in 2004.