Womack was suffering from colon cancer and diabetes at the time of his death, a representative for Womack's label XL Recordings said.
The child of two musicians, he began his career as a member of Curtis Womack and the Womack Brothers, who were signed to legendary R&B singer Sam Cooke's label. The group changed their sound from gospel to a more pop sound and also changed their name to The Valentinos. Their hit song, 1964's "It's All Over, became a huge hit for the Rolling Stones who covered it a month later.
Womack left the group the following year and released his debut album, Fly Me to the Moon in 1968. He went on to release a slew of successful albums in the early '70s, including Understanding Across 110th Street, Facts of Life and Lookin for Love Again.
In 1981, Womack enjoyed one of his biggest hits yet with "If You Think You're Lonely Now." However, he battled drug addiction for most of the decade and eventually checked into rehab.
Womack received critical acclaimed for his 2012 album, The Bravest Man in the Universe. He was inducted into the Rock and Roll Hall of Fame in 2009.